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298 Cards in this Set
- Front
- Back
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primary skin lesions
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- macules, patches - papules, plaques - nodules, tumors - pustules - vesicles, bullas - wheals - cysts |
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macule/patch
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- area of altered pigment - flat, level w/ the skin - normal skin texture and architecture - ...basically a freckle - macules are small (<1cm), patches are bigger (>1cm) |
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papule
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- solid elevated mass - most papule lesions are centered on hair follicles --> folliculitis - <1cm in diameter |
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common ddx for papules
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- Staphylococcal disorders - parasitic disorders - dermatophytosis |
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nodule
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- solid elevated mass - >1cm in diameter |
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common ddx for nodules
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- Staphylococcal disorders - fungal disorders - neoplastic conditions - sterile disorders |
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plaque
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- flat-topped, solid, elevated masses w/ gradually sloping walls
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wheal
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- flat-topped boggy mass - pits w/ pressure (filled w/ edematous fluid) |
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pustule
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- fluid-filled lesion filled w/ pus - pus = degenerate PMNs, other WBCs |
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common ddx for pustules
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- Staphylococcal disorders - sterile disorders |
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vesicles/bullas
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- fluid-filled lesions, that aren't filled w/ pus - ...basically blisters - vesicles are small <1cm - bulla are bigger >1cm |
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common ddx for vesicles
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- sterile disorders - vascular disorders - neoplastic conditions |
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cysts
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- can be congenital or acquired - multiple different kinds - diagnosed by examination of the cyst wall |
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alopecia
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- complete hair loss
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hypotrichosis
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- less than normal #s of hairs
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hypertrichosis
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- increased #s of hairs
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scale
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- accumulation of exfoliated epithelial cells
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crust
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- dried liquid +/- cells on the skin's surface
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comedo
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- dilated hair follicle filled w/ keratin - blackheads are open - milia are closed |
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hair cast
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- hair follicle filled w/ keratogenous plug extending above the skin's surface - indicative of a disorder of follicular keratinazation |
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ddx assoc. w/ hair casting
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- seborrhea - follicular parakeratotic hyperkeratosis - Vit A excess/deficiency - sebaceous adenitis - demodicosis - dermatophytosis - follicular dysplasia |
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secondary skin lesions
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- epidermal collarettes - excoriations - erosions, ulcers - fissures - scars - lichenification - callus |
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epidermal collarette
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- "footprint" of a pustule or vesicle - not a good lesion to sample |
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excoriations
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- self-induced lesions - caused by the animal: scratching, chewing, licking, rubbing, rolling |
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ulcers/erosions
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- loss of epidermal +/- dermal tissue - erosions: above the BMZ - ulcers: below the BMZ - fissures are linear ulcers |
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lichenification
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- sign of chronicity - lesions are often hyperpigmented |
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callus
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- hypertrophied fibrotic material - found over bony prominences - form to protect the underlying tissues |
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configuration of lesions
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- annular - arciform - polycyclic - linear - serpiginous - central healing |
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surface sampling
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- fecal float - combing - acetate tape - Q-tip swabbing - direct impression - skin scraping |
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skin scrapings
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- useful for identifying external parasites - false negatives are common - multiple techniques used/available |
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trichogram
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- select typical areas - sample 10-15 hairs - mount in mineral oil normal trichogram should have: - mix of anagen and telogen hairs, and primary and secondary hairs - normal hair shaft anatomy - appropriate pigmentation - little to no follicular debris |
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hair growth cycle
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- hair growth is triphasic - anagen, catagen, telogen - ratio of hairs in each phase changes with breed, season, state of health |
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cytology
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- useful in inflammatory and neoplastic conditions - prereq. for c/s testing - various collection techniques: touch prep, swab, FNA |
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fine needle aspiration
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- used to collect samples from solid or deep lesions - suction or trocar methods |
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cytospin cytology
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- used to sample fluid filled lesions - microhematocrit tubes and centrifuge used - avoid bloody or viscid fluids |
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diascopy
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- used to differentiate between vascular dilatation and vascular leakage - red skin caused by vascular dilatation blanches w/ pressure - red skin caused by vascular leakage does not blanch w/ pressure |
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dermatophyte test medium
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- modified Sabouraud's agar w/ pH indicator to detect the dermatophyte - protein metabolism produces alkaline metabolites --> pH change cause red color change - color change and colony growth occur simultaneously - need to check plates every day, be sure to see color change when it first appears; other pathogens will produce color change after longer periods of growth |
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bacterial c/s testing
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- cytology should always precede culture - indicated when: organism can't be ID, rational tx are ineffective, tx options vary greatly in expense - culture intact lesions - use a reliable lab |
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skin biopsy
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- underutilized dx - inflammatory lesions should be examined by a veterinary dermatopathologist - incisional or excisional biopsy techniques - biopsy punches are contraindicated in deep or fragile lesions |
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pathologic process of papules/pustules/crusts
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- invasion of the follicle wall (mural folliculitis) - progression into the follicle lumen (luminal folliculitis) --> makes pus --> pustule - rupture of pustule --> crust OR rupture of hair follicle wall --> furunculosis |
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neutrophilic pustular disorders
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- bacterial infections - fungal infections - Leishmaniasis - viral infections - Pemphigus foliaceous & erythematosus - drug reactions - subcorneal pustular dermatosis - Sweet syndrome - superficial suppurative necrolytic dermatitis - linear IgA pustular dermatitis - some other autoimmune disorders |
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eosinophilic pustular disorders
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- pemphigus foliaceus & erythematosus - pemphigus vegetans - drug reactions - sterile eosinophilic pustulosis - sterile eosinophilic folliculidites - sterile eosinophilic pinnal folliculitis - allergic contact dermatitis - idiopathic linear papulopustular acantholytic dermatosis |
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commonest causes of folliculitis in dogs, cats, pigs
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- Staph infections - demodicosis - dermatophytosis (order varies by species) |
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commonest causes of folliculitis in horses, ruminants
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- dermatophytosis - dermatophilosis - Staph infections |
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impetigo
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- "puppy pyoderma" - NONfollicular bacterial (Staph spp.) pustular disease - doesn't bother dog - self-limiting |
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Staphylococcal folliculitis & furunculosis
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- pre-existing condition needed for infection (i.e. immune deficiency, metabolic disorder, skin disease) - common species: S. pseudintermedius, S. aureus, S. schleiferi - Staph does not normally inhabit/infect face |
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regionalized furuncular disorders
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- nasal - chin and muzzle - post-grooming - mucocutaneous - acute moist folliculitis & furunculosis - acral lick furunculosis - pedal |
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nasal furunculosis
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- can occur secondary to nasal trauma (i.e. pruritic disorders, rodent hole burrowing) - a slowly progressive disorder --> take about a week or so for bacterial disease to progress - painful or pruritic - heals w/ scarring |
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chin & muzzle furunculosis
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- "canine acne" - common in "bristly" coated breeds - initiated by trauma to the chin region (i.e. frisbee, tug-of-war, eating/drinking behaviors) - initially sterile ingrown hairs causing the lesion - heals with scarring |
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post grooming folliculitis & furunculosis
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- common in short-coated breeds - occurs 12-24 hours after bathing - caused by contaminated shampoos, bathing utensils, or tap water - usu. painful w/ systemic signs of illness - more often Pseudomonas spp. (not Staph.) |
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mucocutaneous staphylococcal pyoderma
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- chronic, recurrent - common in German Shepherds - infections start at a mucocutaneous junction (i.e. lips, nares, eye lids) |
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acute moist folliculitis & furunculosis
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- mimics acute, moist dermatitis ("hot spot) - sudden onset of self-trauma to otherwise normal skin - painful - distinguish from hot spot by: palpation (follicular/furuncular lesions are thicker than surrounding skin), presence of satellite lesions (hot spots do not have satellite lesions) |
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acral lick folliculitis & furunculosis
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- occurs after behavioral issues, skin trauma, or deep seated skin disease - hairs become deeply imbedded - heals w/ scarring |
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pedal furunculosis
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- triggered by: foot conformation, pruritic pedal disorders, environmental factors - progressive disorder - heals w/ scarring |
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feline Staphylococcal infections
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- not common - mimics noninfectious miliary dermatitis - secondary to: pruritic skin disorders, chronic corticosteroid use |
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equine Staphylococcal infections
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- not common - can occur following: skin damage, overzealous treatments by owners |
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manifestations of Dermatophilosis
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- streptothricosis - rain scald - rain rot - lumpy wool - strawberry foot rot - mycotic dermatitis - aphis |
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otitis
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- inflammation can be sterile or w/ infection - otitis externa --> affecting the tissues from the pinna to the tympanic membrane - otitis media --> affecting the tissues comprising or contained w/in the middle ear cavity |
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cerumen
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- yellow, waxy substance made up of the secretions from ceruminous and sebaceous glands, and desquamated keratinocytes - aka ear wax |
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glandular hyperplasia
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- an increase in the number of glandular cells - typically incited by inflammation |
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stenosis
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- abnormal narrowing of a structure
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fibrosis
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- excessive fibrous connective tissue formation in a reparative or reactive process
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dystrophic mineralization
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- calcium deposition within cells resulting in phosphate accumulation and microcrystal formation - occurs in response to tissue damage |
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primary causes of otitis externa
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- primary causes are agents that induce otitis in a NORMAL ear ex: - hypersensitivity disorders - parasites - foreign bodies - keratinization disorders - immune-mediated diseases |
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hypersensitivity induced otitis externa
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- most common cause of OE in dogs - can include: atopic dermatitis, food hypersensitivities, contact hypersensitivities, adverse cutaneous drug reactions |
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parasite induced otitis externa
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- mites: Otodectes cynotis, Demodex sp., Sarcoptes sp., Notoedres cati, "chiggers" - ticks: spinose ear tick - flies: stable fly, deer fly |
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keratinization disorder induced otitis externa
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- can be caused by: chronic ceruminous otitis externa, idiopathic seborrhea, hypothyroidism
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secondary causes of otitis externa
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- secondary causes are agents that induce otitis in an ABNORMAL ear ex: - bacteria: Staph. pseudintermedius, Pseudomonas, Proteus, E. coli, Klebsiella - yeast: Malassezia pachydermatis, Candida sp. - topical acquired irritant reactions |
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factors predisposing to otitis externa
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- ear conformation - increased relative humidity is most important factor; hairy ear canals - excessive moisture - increased humidity, swimming, contaminated water - obstructive ear disease - nasopharyngeal polyps, ceruminous cystomatosis, ceruminous gland neoplasms - primary otitis media |
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factors perpetuating otitis externa
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- progressive pathologic changes - glandular hyperplasia, stenosis, fibrosis, etc. - tympanic membrane alterations - otitis media |
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normal ear cytology (cat, dog)
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- yeast: median of 0.2 yeast per HPF - bacteria: 0-0.3 cocci per HPF; no rods - corneocytes w/ small #s of nucleated keratinocytes |
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bacterial infection
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- evidence of organisms w/in inflammatory cells on cytology
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bacterial overgrowth
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- evidence of organisms on cytology, but not within inflammatory cells
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indications for c/s when tx OE
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- severe OE w/ rods seen cytologically - poor response to appropriate therapy - presence of otitis media - cytology should always be performed first! |
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indications for otoscopy/myringotomy when tx OE
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- poor response to therapy - otitis media --> myringotomy, culture, flush - mass/FB --> potential removal or biopsy |
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indications for advanced imaging when tx OE
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- further assessment of potential otitis media - pre-sx planning |
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tx of OE
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- correct/manage underlying causes/factors - cleaning - topical therapy - systemic therapy - surgery - follow-up |
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indications for systemic tx of OE
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- presence of parasites - severe or refractory cases of OE - marked proliferative changes - owner can't administer topical tx - topical adverse rxns are present or suspected |
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sx tx interventions for OE
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- lateral ear canal ablation - total ear canal ablation +/- bulla osteotomy |
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techniques for draining an aural hematoma
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- teat cannula - suction drain - multiple perforations w/ skin punch, laser - multiple aspirations - plastic rivets - incision w/ through-and-through sutures |
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aural hematoma
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- accumulation of blood, intracondrally, within the pinna - secondary to head-shaking/trauma - often assoc. with otitis externa |
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surgical technique for aural hematoma
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- pt is anesthetized - ear canal examined (must tx underlying OE), pinna clipped and prepped - incision made over the hematoma - fibrinous material removed from hematoma to improve cosmetic result - full thickness sutures are placed parallel to long axis of the incision to minimize ligation of the auricular blood supply - sutures are placed through a non-adherent pad (or buttons!) - left on for 3 wks - wrap can be applied over ear/head to reduce head shaking |
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lateral ear canal resection
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- sx tx option for non-responsive OE - horizontal ear canal must be patent - provides improved drainage of ear canal, reduces humidity in canal - 50% effective - most still require med tx to control ear disease |
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lateral ear canal resection - sx technique
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- pinna, ear canal and skin over canal are shaved/prepped - skin incisions made cranial and caudal to tragus; length of incision is 1.5x length of vertical canal - skin flap dissected from SQ - dissection to level of parotid salivary gland - parallel incisions in lateral wall of canal create hinge at junction of vertical/horizontal canals and expose entrance to horizontal canal - skin sutured to canal walls - post-op analgesia, head wrap 3-5 days, abx for 14 days, sutures removed 10-14 days |
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vestibular signs indicating inner ear involvement
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- head tilt - circling - nystagmus (quick phase away from lesion) |
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feline inflammatory polyps
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- common in cats age 1-3 y.o. - often hx of URTI - polyps originate in middle ear - poss. immune-mediated rxn to upper resp. virus - CS depend on which way the polyps extend: chronic OE, upper resp. signs, Horner's syndrome, vestibular signs |
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extraction of feline polyps
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- lateral polyps can be extracted through ear canal - 13-40% recurrence - nasopharyngeal polyps extracted through mouth - 10-41% recurrence - steroids may reduce/prevent recurrence |
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indications for TECA
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- non-responsive OE w/ severe epithelial hyperplasia - neoplasia in the ear canal - revision of failed lateral ear canal resection |
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`TECA sx technique
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- T-shaped incision made over ear canal - incision made that encircles the external ear canal - excise ear canal w/ carfeul dissection near facial n. - skin is closed - post-op analgesia, head wrap for 3-5 days, E-collar, 3 wks of abx |
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complications of TECA
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- 10% facial nerve paralysis - <5% facial fistula - <1% vestibular signs - 100% hearing loss in affected ears |
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when and why to take a skin biopsy
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- if skin lesions are acute and severe - if the tx for a disorder is assoc. w/ sig. side effects or potentially life-threatening - if you suspect a neoplastic process - if skin lesions appear unusual - if new lesions develop while on therapy - if lesions fail to respond to tx |
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where to take a skin biopsy
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- biopsy primary lesions - biopsy multiple sites and a range of lesions |
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preparing to take a biopsy
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- may need abx 2-3 wks before biopsy - eliminate secondary infections that may mask pathology - stop PO/topical steroids 2-3 wks before and injectable steroids 6 wks before biopsy |
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biopsy techniques
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- trim hair, but not too close - never scrub the surface! - use local anesthetic - use 6-8mm biopsy punch for haired skin - use 4mm biopsy punch for footpad, nasal planum, near eyes/eyelids - use elliptical/wedge biopsies for fragile and deep lesions |
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taking a biopsy of an area of depigmentation
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- take a margin - an area where it is actively depigmenting |
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taking a biopsy of an area of alopecia
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- take a biopsy of 1) an area of alopecia, 2) an area of hypotrichosis, and 3) a normally haired area for comparison
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taking a biopsy of an ulcer/erosion
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- take a wedge biopsy from the junction of the ulcerative and non-ulcerative skin
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DON'Ts of skin biopsy
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- don't prep/scrub - don't clip the hair too close - don't crush/squeeze the samples - don't use resterilized punch biopsy instruments - don't use cautery on small samples - don't ship samples over the weekend during the winter --> freezing - don't use punch biopsies on fragile or deep lesions - take a wedge or elliptical sample |
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hyperkeratosis
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- epidermal change - increased thickness of the stratum corneum - orthokeratotic - no nuclei - parakeratotic - have retained nuclei |
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epidermal hyperplasia
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- epidermal change - aka acanthosis - increased thickness of the non-cornified epidermis due to an increased # of epidermal cells - can be: regular, irregular, psoriasiform, papillated, pseudocarcinomatous |
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apoptosis
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- intentional cell suicide - non-inflammatory - activated by growth factors, cytokines, hormones, immune system, viruses, sublethal cell damage - can be seen in small #s in any hyperplastic epidermis |
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intercellular edema
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- epidermal change - "spongiosis" - widening of intercellular spaces, formation of spongiotic vesicles - common in acute or subacute inflammatory dermatosis |
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intracellular edema
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- epidermal change - increased size, cytoplasmic pallor, displacement of nucleus - common feature of acute or subacute inflammatory dermatosis |
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ballooning degeneration
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- epidermal change - "koilocytosis" - type of degeneration seen in epidermal cells - swollen, stippled cytoplasm w/o vacuolization - enlarged or condensed, sometimes multiple, nuclei - specific feature of viral infections |
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hydropic degeneration of basal cells
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- epidermal change - intracellular edema in the stratum basale - uncommon finding |
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acantholysis
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- epidermal change - loss of cohesion between epidermal cells --> clefts, vesicles, bullae |
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exocytosis
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- epidermal change - migration of inflammatory cells or erythrocytes through the intercellular spaces of the epidermis - common feature of any inflammatory dermatosis |
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microvesicles, vesicles, bullae
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- epidermal change - fluid-filled, relatively acellular spaces - can be caused by intercellular edema, ballooning degeneration, acantholysis, hydropic degeneration, subepidermal edema or autoantibodies |
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microabscesses and pustules
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- epidermal change - cavities w/ inflammatory cells - pustules are grossly bigger than miscroabscesses |
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crusts
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- epidermal change - consolidated dessicated surface mass composed of keratin, serum, cellular debris and microorganisms - can be serous, serocellular, cellular, hemorrhagic, palisading - crusts indicate a prior exudative process |
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changes seen in collagen
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- hyalinizaton - lysis and loss of structural details - dystrophic mineralization - atrophy - dysplasia - "flame figures" |
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pigmentary incontinence
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- dermal change - melanin granules free w/in the subepidermal and perifollicular dermis and w/in macrophages - can be seen in any process that damages the stratum basale and the BMZ |
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edema |
- dermal change - dilated lymphatics, widened spaces btwn blood vessels and perivascular collagen, or widened spaces between areas of collagen - common in any inflammatory dermatosis |
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mucinosis
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- dermal change - large amounts of amorphous, stringy, granular, basophilic material that separates, thins, or replaces dermal collagen fibrils and surrounds blood vessels and adnexae |
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perivascular dermatitis
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- superficial is more common - hypersensitivity, ectoparasites, dermatophytosis, dermatophilosis, nutritional deficiencies, seborrheic disorders, contact dermatitis - deep is less common - systemic disorders, severe local reactions |
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interstitial dermatitis
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- infiltration of cells btwn collagen bundles of the dermis - infiltrate is poorly circumscribed, mild to moderate, does not obscure anatomy of the skin |
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vasculitis
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- immune and non-immune mechanisms - most thought to be immune-complex or type-III hypersensitivity |
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nodular dermatitis
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- discrete clusters of cells
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diffuse dermatitis
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- denotes a cellular infiltrate so dense that discrete cellular aggregates are no longer easily visualized and the anatomy of the skin is obscured
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interface dermatitis
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- dermoepidermal junction is obscured by hydropic degeneration, lichenoid cellular infiltrate, or both
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intraepidermal vesicular and pustular dermatitis
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- most useful to classify intraepidermal vesicles and pustules to their anatomic level of occurrence w/in the epidermis
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perifolliculitis
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- accumulation of inflammatory cells around a hair follicle
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folliculitis
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- mural folliculitis: wall of the follicle is targeted - luminal folliculitis: accumulation of inflammatory cells w/in the lumen |
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furunculosis
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- follicular rupture - most commonly occurs as a result of luminal folliculitis - usu. assoc. w/ pyogranulomatous inflammatoin, eosinophils --> FB rxn to free keratin and hair shafts |
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atrophic dermatosis
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- characterized by varying degress of epithelial and connective tissue atrophy - may show following histopath changes: hyperkeratosis, atrophy, follicular keratosis, follicular atrophy, telogenization, flame follicles, epithelial melanosis, sebaceous gland atrophy |
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panniculitis
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- inflammation of the subcutis
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cause of dermatophytosis
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- Microsporum spp. and Trichophyton spp. infect animals most frequently - M. canis most common in cats, dogs |
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pathogenesis of dermatophytosis
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- more common in hot, humid climates - more common in very young, old, or immunocompromised - transmitted through contact w/ infected animals, environment, or fomites - arthrospore is infective portion - surives up to 18 mos. in environment - spore invades anagen hair follicle, adheres to keratin and germinates - clinical lesions appear in 7-14 days |
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dermatophytosis in dogs
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- less than 5% of derm cases - usu. in dogs less than 1 y.o. - infection usu. localized to face, pinnae, paw, tail - variably pruritic |
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sylvatic ringworm
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- acquire from wildlife - more common in adults - M. persicolor, T. mentagrophytes |
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other lesions assoc. with canine dermatophytosis
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- onchomycosis - rare, more common w/ sylvatic spp. - fungal kerion on face or distal limbs |
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feline dermatophytosis
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- #1 dermatitis in cats - annular areas of alopecia, +/- scales - lesions on head, pinnae, paws - most common in young cats <1 y.o. - variably pruritic |
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other lesions assoc. with feline dermatophytosis
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- onchomycosis - rare - widespread, severe alopecia w/ little inflammation - pruritic military dermatitis - chin folliculitis - seborrheic-like eruption - resembling pemphigus foliaceous |
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equine dermatophytosis
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- #2 dermatitis in horses, ~9% of skin disease - Trichophyton equinum most common - usu. in animals <2 y.o. - usu. minimally pruritic - lesions on face, beck, dorsolateral thorax and girth - lesions usu. multifocal, rarely generalized |
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bovine dermatophytosis
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- Trichophyton verrucosum most common - usu. in animals <1 y.o. - more common in fall, winter in confined animals - crusted papules --> thick gray crusts on face, head, pinnae, neck, rump, tail, perineum |
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caprine dermatophytosis
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- Trichophyton verrucosum most common - usu. in animals <1 y.o. - lesions on face, head, pinnae, neck and legs |
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porcine dermatophytosis
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- Microsporum nanum most common - brown to orange annular crusts on face, pinnae, trunk - alopecia and pruritus are rare |
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dx of dermatophytosis
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- hx - PE: folliculitis - Wood's lamp... lots of false + and - - scrapes and trichograms - fungal culture - most reliable - biopsy |
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dermatophyte fungal culture
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- Dermatophyte test medium - Sabouraud's dextrose agar + antimicrobial agents to deter growth of other organisms - phenol red in agar turns red as fungus grows and produces alkaline metabolites |
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goals of dermatophyte treatment
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- maximize the pt's ability to respond to tx - good nutrition, tx underlying conditions, avoid immunosuppression - reduce contagion - hasten resolution of the infection - in-contact animals - environment |
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Malassezia dermatitis
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- M. pachydermatis part of normal flora in dogs, cats - found in haired skin, ear canals and mucosal areas - underlying causes: atopic dermatitis, food allergy, endocrinopathy, keratinization disorders, metabolic disease, corticosteroids - causes hypersensitivity in dogs - pruritic, alopecia, excoriations, erythema, seborrhea, lichenification, hyperpigmentation, hyperkeratotic |
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dx of Malassezia
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- hx - PE - smears/impression/tape - culture (normal flora) - biopsy - response to tx |
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tx of Malassezia
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- address predisposing causes - topicals for localized dz - systemic antifungals for severe, generalized, chronic or deep infections |
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nodules
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- circumscribed, solid lesions greater than 1cm in diameter - may be elevated above skin's surface or completely SQ - nodules can also be described as tumors... |
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tumors
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- defined as a swelling of part of the body - abnormal benign or malignant new growth of tissue |
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plaques
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- circumscribed, solid, elevated and flat-topped
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causes of nodules, tumors, plaques
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- inflammation - neoplasia - cysts - hamartomas - benign focal malformations, resemble neoplasms |
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sterile granuloma syndrome
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- common in cats, dogs, horses - cause usu. unclear - on cytology: granulomatous, pyogranulomatous, eosinophilic - culture to exclude infection |
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feline eosinophilic granuloma complex
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- reaction pattern, not a dx - causes can include: allergies to environment, food, fleas, mosquitoes; idiopathic - common cutaneous, mucocutaneous, oral mucosal lesion of cats - papular, nodular, raised oval to linear plaques - firm, erythematous to orange-yellow - chin and caudal thighs are common sites |
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feline eosinophilic plaques
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- severely pruritic - well-circumscribed, raised, erythematous, eroded, oozing, often ulcerated - oval to linear - abdomen and medial thighs most common |
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feline indolent ulcer
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- common oral mucosal lesions - usu. near upper lip near philtrum - may be early reaction to flea allergic dermatitis |
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equine eosinophilic granuloma
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- common in spring, summer - round, elevated, well-circumscribed - non-painful, non-pruritic - caused by: hypersensitivity, trauma, body-clipping, injection sites |
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Habronema
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- common cause of eosinohilic granulomas in horses - pruritic - possibly a hypersensitivity rxn |
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panniculitis
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- most cases are sterile and idiopathic - other causes: infectious, drug reactions, vaccine and other injections, FB, pancreatitis, neoplasia, nutritional deficiencies, trauma, burns - most common in dogs; cats, horses - commonly occurs on the trunk |
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cutaneous cysts
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- non-neoplastic, simple sac-like structure with an epithelial lining - usu. solitary lesions - common in head, neck, trunk, proximal limbs - can be: follicular, epithrichial, dermoid, sebaceous |
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follicular cysts
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- well-circumscribed, round, smooth, firm to fluctuant lesions - dermal to SQ - can arise from different portions of the hair follicle (i.e. infundibular, isthmal, matrical...) |
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epithrichial gland cysts
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- common in dogs; uncommon in cats - caused by duct obstructions - well-circumscribed, smooth, tense to fluctuant lesions - may be alopecic w/ a blue hue - common on head, neck and limbs |
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dermoid cysts
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- developmental abnormality, congenital, hereditary - lesions can be solitary or multiple - lesions often along dorsal midline |
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sebaceous gland cysts
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- rare - occur in sebaceous ducts - solitary, firm, <1 cm |
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trichoblastoma (basal cell tumors)
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- common in adult/old cats - usually benign - freq. melanotic - may be alopecic, ulcerated |
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sebaceous gland tumors
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- nodular hyperplasia - adenomas, epitheliomas, carcinomas - common in adult/old dogs - smooth, shiny pink to orange papules --> cauliflower-like - +/- hyperpigmented, ulcerated |
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epitrichial sweat gland tumors
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- adult dogs, cats - can be benign or malignant - solitary lesions on head, neck, trunk, limbs - commonly blue, cystic - may be solid, ulcerated |
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lipoma
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- very common in adult/old dogs - common on trunk, abdomen, proximal limbs - well-circumscribed, soft to firm, SQ |
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mast cell tumors
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- common in dogs - dermal or SQ - variable appearance and biologic behavior |
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histiocytoma
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- common in dogs under 2 y.o. - tumors of Langerhans cells - usu. solitary lesions on head, pinnae, limbs - appear suddenly, often ulcerated - spontaneous remission in several months |
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melanocytic neoplasms
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- 70% are benign - usu. solitary masses on head, trunk - lesions on digits, scrotum, lips more commonly malignant |
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equine melanoma
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- common in old gray horses on perineum, tail, pinna, periocular, distal limbs - 2/3 metastasize eventually, freq. w/o clinical signs |
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equine sarcoids
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- most common equine skin neoplasm - occur commonly on inguinal area, head, axilla, abdomen, thorax, neck, distal limbs - locally aggressive, but not metastatic - genetic, viral, trauma - can be occult, verrucous, nodular, fibroblastic, malevolent |
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pruritus
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- unpleasant sensation that provokes the desire to scratch - physiologic or pathologic - pruritic and painful stimuli carried on same nerve fibers |
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methods of itching in animals we treat
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- scratching - licking - chewing - rubbing - rolling |
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triggers for "pruritus"
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- behavioral disorders - orthopedic disease - neurologic disease - skin disease - lesional or "normal" skin |
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behavioral skin dz
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- rare - always assoc. w/ other behavioral signs |
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neurogenic/orthopedic skin disease
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- uncommon to rare - localized - variable speed of onset and intensity of pruritus |
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common lesionless pruritic disorders in dogs
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- flea bite hypersensitivity - atopic dermatitis - food hypersensitivity - Cheyletiella infestation - Demodex injae infection |
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common lesionless pruritic disorders in cats
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- flea bite hypersensitivity - Cheyletiella infestation - atopic dermatitis - food hypersensitivity - Demodex gatoi infestation |
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common lesionless pruritic disorders in horses
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- Culicoides hypersensitivity - Chorioptic mange - atopic dermatitis |
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common lesionless pruritic disorders in farm animals
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- Chorioptic mange - P. tenuis |
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flea dermatitis
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- CS due to irritation or allergy - pruritic papular eruptions on: dogs - rump, inguinal, posterior thighs; cats - neck, rump |
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atopic dermatitis
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- genetically predisposed inflammatory and pruritic skin disease w/ CS assoc. w/ IgE antibodies most commonly to environmental allergens
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atopic-like dermatitis
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- genetically predisposed inflammatory skin disease w/ CS identical to atopic dermatitis in which IgE antibodies to environmental allergens are not demonstrable - ...atopic dermatitis that you can't attribute to environmental allergens |
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canine atopic dermatitis
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- early onset (6-36 mos.) - breed disposition, family hx - seasonal --> increased severity and duration - CS: recurrent OE, pruritus of face, ears, feat, axilla, inguinal area; Staph pyoderma, Malassezia dermatitis, pyotraumatic dermatitis, acral lick dermatitis, anal sacculitis, hyperhidrosis |
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feline atopic dermatitis
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- onset between 1-3 y.o. - can have lesional or non-lesional pruritus - protracted seasonality - CS: pruritic otic dz, pruritus of face, head and neck; miliary dermatitis, traumatic alopecia, eosinophilic granuloma complex |
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equine atopic dermatits
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- early age onset (1.5-6 y.o.) - seasonal or non-seasonal at onset - presents variably - nonlesional pruritus, urticaria, symmetrical eosinophilic folliculitis |
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dx, tx of atopic dermatitis
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dx: - hx, PE - eliminative testing - allergy testing?? tx: - resolve secondary disorders - removal allergens - medical management w/: glucocorticoids, antihistamines, NSAIDs, cyclosporine, Janus kinase inhibitor (Apoquel) - (should resolve w/ steroids) - allergen-specific immunotherapy |
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food hypersensitivity
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- allergens usu. water-soluble glycoproteins - variable clinical presentation - skin, non-skin, combination - sources of exposure: daily ration, treats, supplements, meds, scavenged foods, "digested" allergens, water |
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CS of canine food allergy
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- CS: urticaria, atopy-like pruritus, OE, acute moist dermatitis, lumbosacral pruritus, scabies-like pruritus
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CS of feline atopy or food hypersensitivity
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- CS: pruritic OE, pruritus or face, head and neck; miliary dermatitis, traumatic alopecia, eosinophilic granuloma complex
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CS of equine food hypersensitivity
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- CS: atopic-like pruritus, non-pruritic urticaria, pruritic urticaria
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Cheyletiellosis
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- ectoparasite w/ caudo-dorsal distribution - 3 wk life cycle - eggs cement to hair shaft - CS: none --> seborrhea +/- pruritus --> scabies-like pruritus |
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canine demodicosis
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- D. injae - initial lesions present in sebaceous regions - face, chin, feet, dorsal midline - non-pustular, facial and pedal pruritus |
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feline demodicosis
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- D. gatoi - ectoparasite - contagious - CS variable - lesions start ventrally and move dorsal |
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causes of tailhead rubbing in horses
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- Culicoides hypersensitivity - pediculosis (lice) - stall vice - psoroptic mange - oxyuriasis (pin worms) - allergy |
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control of Culicoides
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- environmental changes - mosquito traps - body suit - on-horse insecticides - selective stabling - paddock fans |
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Chorioptic mange
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- common in winter - 21 day life cycle - can survive off host for 70 days - tx: clean environment, tx everyone, topicals best (permethrin sprays, selenium sulfide shampoo, fipronil spray, lime sulfur dips) |
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disorders of keratinization
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- altered epidermal turnover - altered epidermal hydration - altered epidermal differentiation - altered lipid formation or deposition - any combination thereof |
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antiseborrheic therapy
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- ID and resolve triggering event - topical and systemic agents can treat seborrhea - tx secondary bacterial or yeast dermatitis |
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antiseborrheic bathing
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- results of bathing influenced by: frequency, thoroughness and the shampoo used - a prebathing bath may be beneficial - contact time w/ the shampoo is important: 10-15 minutes |
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primary disorders of keratinization in dogs
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- ichthyosis - follicular parakeratosis - epidermal dysplasia - primary seborrhea - primary sebaceous hyperplasia - sebaceous adenitis - ectodermal dysplasia |
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primary disorders of keratinization in cats
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- ichthyosis - primary seborrhea |
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ichthyosis
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- rare - onset at, near birth - flaky skin, large plates of scales, worse in "seborreic trouble spots" - interdigital, axilla, skin folds... |
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follicular parakeratosis
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- rare - only affects females - are often stunted and have other non-cutaneous defects |
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epidermal dysplasia
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- only in Westies - keratinization defect w/ susceptibility to Malassezia hypersensitivity - onset between 6-12 mos. - variably greasy and pruritic |
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control of Malassezia
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- topical agents (i.e. chlorhexidene, miconazole, ketoconazole, zymox, enilconazole) - systemic agents (i.e. -conazoles, terbinafine) - therapeutic of maintenance protocols |
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canine generalized primary seborrhea
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- early onset in life - involves al keratinized surfaces - worsens with age - very susceptible to secondary bacterial or yeast infections - no systemic complaints |
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ectodermal dysplasia
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- congenital abnormality of pilosebaceous unit - results in follicular hypoplasia, abnormal sebaceous and/or epitrichial sweat glands - worsens with age- tx: moisturizers, topical kerolytics, systemic agents |
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canine generalized secondary seborrhea
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- common - can onset at any point in life - may involve all keratinized surfaces - very susceptible to secondary bacterial or Malassezia infections - can have variable systemic signs |
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feline generalized secondary seborrhea
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- low incidence - can onset at any point in life - may not involve all the keratinized surfaces - very susceptible to secondary bacterial or Malassezie infections - can have variable systemic signs |
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exfoliative dermatoses
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- many different causes - indicative of serious disease - epidermis comes off in large sheets |
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localized acquired disorders of keratinization in dogs
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- callus - nasodigital hyperkeratosis - ear margin dermatosis - tail gland hyperplasia |
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localized acquired disorders of keratinization in cats
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- feline acne - tail gland hyperplasia |
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callus
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- hyperkeratotic plaques over pressure points - environmental trigger - not a medical problem |
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senile nasodigital hyperkeratosis
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- common - middle to old dogs - uncommonly symptomatic - does not typically require tx - can try hydration (Vaseline) or keratolytic products |
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feline acne
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- common - single, multiple or persistent episodes - usually doesn't bother cat at all - chronic cases should be checked for Malassezia, Demodex - tx: manual evacuation, topical keratolytics, systemic glucorticoids, abx or retinoids |
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hypotrichosis
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- condition of abnormal hair loss
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hypertrichosis
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- abnormal amount of hair growth
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alopecia
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- partial or complete absence of hair from areas of the body where it normally grows
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mechanisms of hair loss
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- trauma - hair follicle inflammation - hair follicle irregularity |
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endocrine hair loss
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- variable systemic signs - coat changes due to: altered hair follicle growth rate, altered hair follicle cycle, hair follicle receptor interactions |
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canine hypothyroidism
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- most common endocrine disease - T4 needed to institute anagen phase of hair cycle - hairs already in anagen show decreased growth rate - hair loss first occurs in frictional areas - CS: lethargy, dullness, weight gain, heat seeking, skin changes, CV signs, neuropathy, myopathy, repro system irregularities |
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feline thyroid disease
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- hypothyroidism: rare - hyperthyroidism: uncommonly see skin signs |
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canine hyperadrenocorticism
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- predictably progresses from systemic signs --> altered hair coat --> hair loss - excess steroids result in: decreased sebum secretion, decreased epidermal turnover, slowed hair growth, delayed hair regrowth, altered coat color, comedones - CS: pu/pd, polyphagia, hepatomegaly, pot-bellied, skin changes, anesterus/testicular atrophy, virilization, hypertension, excessive bruising, poor wound healing, secondary infection, increased panting, neuro signs |
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feline hyperadrenocorticism
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- rare - skin changes variable and atrophic |
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gonadal sex hormone disorders
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- systemic signs usually absent - results in patterned alopecia - variable coat color alteration - androgen and estrogen receptors on hair follicles vary w/ # and affinity w/ gender and body site |
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male pattern alopecia
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- rump - caudal thighs - collar - shoulders |
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female pattern alopecia
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- flank - caudal thighs - ventrum - back of head |
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gonadal disorders of intact female
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- hyperestrogenism - hyperprogesteronism - cutaneous pseudocyesis - primary anestrous - estrogen responsive alopecia |
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hyperestrogenism
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- caused by ovarian tumors, cysts - signs of constant estrus, acromegaly, DM - patterned alopecia - comedones |
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cutaneous pseudocyesis
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- hair loss starts ~ 6 wks post-estrus - usu. w/ behavioral and/or mammary changes - resolves spontaneously |
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gonadal disorders of intact male
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- testicular neoplasia - "normal" testes - hyperandrogenemia - primary testicular atrophy |
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testicular neoplasia
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- most tumors are benign - estrogens produced by Sertoli cell tumors and seminomas - testosterone produced by interstitial cell tumors |
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Otodectes cyanotis
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- nonburrowing psoroptid mite - 3 wk life-cycle; 2 month lifespan - host non-specific - can be found in ears and on the body - feeds on cell debris and tissue fluid - tx: parasiticidal otic preps, ivermectins, avermectins, isoxazolines |
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Cheyletiellosis
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- non-host specific - 3 wk life cycle - can survive off the host for 10 days - surface parasite, eggs cemented to hair shaft - CS: dorsally-oriented seborrhea, pruritus - dx: fecal float, acetate tape impression, flea comb, skin scrape?? - tx: lime sulfur, fipronil, avermectins |
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canine scabies
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- Sarcoptes scabiei var. canis - 17-21 day lifecycle - off-host survival influenced by temperature and humidity - burrowing, lives w/in epidermis - incubation period of about >30 days - prefers ears, elbows, feet, ventrum and hocks - intensely pruritic - dx: skin scrape - tx: lime sulfur, amitraz, fipronil, avermectins, isoxazolines |
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feline sacbies
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- Notoedres cati or Sarcoptes scabiei - rare - mites are easy to demonstrate- tx: lime sulfur, amitra, fipronil, avermectins |
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demodicosis
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- 3 species: D. canis, D. cornei, D. injae - part of normal fauna - transferred to neonate while nursing, otherwise not contagious between adults - resides in the hair follicle - feeds on sebum and cellular debris - 28-35 day life cycle - dx: skin scraping, trichogram, pustular cytology - tx: symptomatic tx, miticidal agents (Mitiban, avermectins, isoxazolines) |
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localized canine demodicosis
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- uncertain pathogenesis - disease of young dogs - can cause hair loss or ceruminous OE - tx: mild topical agents, ear cleaners, topical parasiticides |
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generalized canine demodicosis
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- serious - disease of the mite-specific immuno-incompetent --> genetic predisposition - clinical presentations: multifocal lesions, facial dermatitis, pododermatitis, seborrhea, widespread dermatitis, pyoderma |
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juvenile-onset demodicosis
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- onset between 3-18 mos. - genetically predisposed - self-curing usu. |
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adult-onset demodicosis
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- onset over 4 yrs - triggered by systemic dz: endocrine disorders, neoplasia, others?? |
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D. injae
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- non-pustular - lesions in "sebaceous" regions (face, chin, feet, dorsal midline) - pruritic - mites are deep in follicle - tx: Mitaban, avermectins, isoxazoline |
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feline demodicosis
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- uncommon - D. cati, D. gatoi, maybe others - tx: lime sulfur, amitraz, ivermectin, Advantage Multi |
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D. cati demodicosis
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- assoc. w/ immunosuppression - follicular or otic - dx: skin scrape - tx: difficult |
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D. gatoi demodicosis
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- surface parasite - contagious - starts on the ventrum - dx: fecal float, tape |
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disorders caused by insects
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- pediculosis - flea dermatitis - fly dermatitis - myiasis - hymenoptera |
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tick control
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- environmental management - manual removal - topicals (fipronil, avermectins, etc.) - collars (Seresto, Scalibor, PReventic) - systemics (ivermectin, selamectin, isoxazolines) |
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pediculosis
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- species specific - 14-21 day life cycles - 1-2 day off host survival - eggs are operculated, cemented to hair shaft - tx: topicals (Advantage, Frontline) |
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fleas
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- numerous spp. and ssp. - feed on blood, bite is irritating/allergenic - vector disease - survivability and rate of development dependent on temp. and humidity - life cycle 21-28 days - tx: treat environment, flea combing, topical insecticides/IGRs, orals |
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flea dermatitis
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- CS due to irritation or allergy - pruritic papular eruptions - dogs: rump, inguinal region, posterior thighs - cats: neck, rump |
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pyrethrins/permethrins
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- insect repellent - can be neurotoxic at high doses - use w/ caution in cats (some are ok, some are not) |
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amitraz
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- acaricide, insecticide and insect repellent - neurotoxic at high doses |
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imidocloprid
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- insecticide
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fipronil
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- insecticide
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avermectins
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- macrocyclic mactone derivatives - anthelminthic, insecticide |
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milbemycins
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- group of macrolides similar to avermectins - anthelminthic, insecticide |
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spinosad - spinetoram
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- insecticidal
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metaflumizone
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- insecticide
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dinotefuran
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- insecticide
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isoxazolines
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- afoxolaner, furlaner, sarolaner - insecticide, acaricide |
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factors impacting selection of a parasiticide
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- site of parasitism - life cycle of parasite - off host survival - feed behavior of parasite - owner issues (i.e. chemical sensitivities) - animals issues (i.e. thick hair coats, no hair, swimming, etc.) |
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Seresto collars
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- anti-flea and tick- rx dispensed over skin in sebum - effective in 24-48 hrs; replace every 8 mos. - cats and dogs - EPA |
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Scalibor collars
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- anti-flea and tick - rx travels over dog through sebum - 2-3 wks to reach efficacy; replace every 6 mos. - dogs only - EPA |
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Preventic collars
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- anti-tick - rx travels over dog through sebum - dogs only - EPA |
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Lime Sulfur
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- antiparasitic, antibacterial, antifungal, antipruritic, keratolytic - used as a dip - always dilute to a 2% solution when using |
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spot-application preventatives
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- easy - product applied over back - nature of skin/coat can impact efficacy - can be distributed on the surface or transdermally, w/ relocation to skin - concentration on skin depends on: time from application, body site, nature of skin |
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Advantage
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- insecticide w/ IGR - fleas, lice - products for dogs and cats - 30 day efficacy, can be applied once a week - EPA - K9 Advantix has arachnicidal properties - Advantage Multi is FDA reg. |
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Frontline
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- insecticide/IGR, arachnicide - cats and dogs - monthly topical - EPA |
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Revolution
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- insecticide, arachnicide, anthelminthic - dog and cat - monthly topical - FDA |
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Capstar
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- insecticide (adulticide only) - oral - rapidly kills exisiting fleas, but does not prevent reinfestation - dogs and cats - FDA |
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Comfortis
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- insecticide - dogs and cats - monthly PO - FDA |
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Nexgard
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- insecticide, acaricide - extra-label use for Demodex, scabies... - monthly PO - dogs only - FDA |
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Bravecto
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- insecticide, acaricide - extra-label use for Demodex, scabies... - every 3 mos. - PO for dogs; topicals for cats, dogs - FDA |
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macrocyclic lactones
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- avermectins, milbemycins - active when ingested by parasites - FDA |
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macules (<1cm) and patches (>1cm)
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papules
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nodule
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plaques
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wheals
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pustules
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vesicle/bulla
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scales
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comedo
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epidermal collarette
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ulcer
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lichenification
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Otodectes (ear mites)
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Demodex canis
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Malassezia
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Demodex injae
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Cheyletiella
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left: lice right: Cheyletiella |
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Sarcoptes scabiei
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Notoedres cati
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Demodex cati
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Demodex gatoi
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sucking louse
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chewing louse
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Ctenocephalides felis felis (fleas)
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nitenpyram
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- insecticidal (adult fleas only)
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