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75 Cards in this Set
- Front
- Back
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What is a macule?
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flat discoloration, < 1 cm
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What is a patch?
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flat discoloration, > 1 cm
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What are causes of macules or patches?
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hyperpigmentation, melanosis
hypopigmentation, leukoderma hemorrhage, hyperemia |
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What is a plaque?
Give an example dz. |
flat, solid, raised, > 1 cm
ex. feline eosinophilic plaques |
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What is a papule?
Give an example dz. |
raised solid discoloration, < 1 cm
ex. bacterial folliculitis & furunculosis |
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What is a nodule?
Give an example dz. |
raised, usually solid discoloration > 1 cm
ex. tumor, inflammation (granuloma), hyperplasia |
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What is a vesicle?
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intra-epidermal/sub-epidermal pocket of fluid, < 1 cm
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What is a bulla?
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intra-epidermal/sub-epidermal pocket of fluid, > 1 cm (rare: often ruptures before you see it)
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Give an example of a disease with vesicles &/or bullae.
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epidermolysis bullosa
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What is a pustule?
Give an example dz. |
intra-epidermal vesicle filled w/ pus
rupture easily b/c of thin epidermis & present as erosions, ulcers, &/or crusts ex. pemphigus foliaceus |
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What is scale?
Give an example dz. |
↑ stratum corneum (hyperkeratosis): white, flaky
ex. sebaceous adenitis |
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What is crust?
Give an example dz. |
desiccated accumulation of keratin, serum, cell debris, hemorrhage, &/or microorgs on skin surface
ex. superficial bacterial pyoderma |
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What is an erosion?
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partial loss of epidermis (very thin)
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What is an ulcer?
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complete loss of epidermis thru basement mem
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Name 2 dz characterized by erosions & ulcers.
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erythema multiforme, vasculitis
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What is lichenification?
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thickening of skin & accentuation of skin surface markings, folds & lines (skin hyperplasia)
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What is atrophy?
Give an example dz. |
thinning of skin d/t loss of epidermal &/or dermal mass
Cushing's: epidermal, dermal, &/or follicular atrophy |
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To what depth does a punch biopsy sample?
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superficial panniculus
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To what depth does a shave biopsy sample?
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superficial dermis
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What are indications for a wedge or excisional bx?
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-deep lesions
-fragile lesions -whenever orientation is essential, esp. lesion margions -to assess invasion (wedge or excisional) |
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What are indications for a shave bx?
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used only for delicate areas (ear, nasal planum) to differentiate epidermal diseases
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How would you bx small lesions such as papules, pustules, & vesicles?
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-bx small lesions in entirety
-center small lesions w/in punch biopsy -take several (6+) biopsies of very small lesions: label “section to center of bx” -use a wedge bx for fragile lesions such as vesicles & pustules |
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How would you bx ulcers?
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-use a deep wedge bx perpendicular to ulcer margin where possible
-bx epidermis at margin of ulcer, central blood vessels deep to ulcer -avoid shallow biopsies in central ulcerated areas -avoid punch biopsies: too shallow, hard to orient for sectioning |
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How would you bx alopecia?
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-bx central, most developed areas of alopecia
-use 8mm punches & collect multiple (6) biopsies -collect 1 bx from normally haired skin at a similar site, particularly for partial or subtle hair loss -mark line of hair follicle growth prior to bx on areas w/ little hair left |
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How would you bx plaques, nodules, or masses?
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-wedge biopsies from actively enlarging, inflamed margins
-bx large masses & plaques at margin -excise small nodules completely -avoid central scarring, necrosis, &/or superficial ulcers |
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How would you bx pannicular lesions?
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wedge bx; biopsy center of lesion
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How would you bx cutaneous hemorrhage?
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-bx center of areas of hemorrhage
-wedge biopsies for large hemorrhages & when deep vascular lesions are suspected -take multiple biopsies: vascular lesions can be small & very hard to hit in histological section -confirm hemorrhage by diascopy -R/O clotting abnormalities prior to bx |
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How would you bx leukoderma?
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-seek areas of recent leukoderma (hx) w/ erythema (active)
-bx active areas of luekoderma at lesion margin |
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How would you bx leukotrichia?
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bx multiple central areas similar to methods used for alopecia, margins if active depigmentation
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What types of skin dz are assoc. w/ neutrophils?
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bacterial pyoderma, pemphigus
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What types of skin dz are assoc. w/ eosinophils?
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hypersensitivity (atopy, FAD, food allergy), parasites, some fungus, oomycetes (Pythium)
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What types of skin dz are assoc. w/ mast cells?
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hypersensitivity, chronic dermal fibrosis (lichenified skin), numerous in normal dermis
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What types of skin dz are assoc. w/ macrophages?
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chronic inflammation, fungal, oomycetes, mycobacterium, foreign body
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What types of skin dz are assoc. w/ lymphocytes & plasma cells?
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chronic inflammation, autoimmune
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perivascular dermatitis
a. what is it? b. causes |
a. inflammatory cells accumulate around reactive blood vessels; most common pattern of inflammation, least diagnostic
b. neutrophilic: R/O bacterial -eosinophilic: hypersensitivities (atopy, food allergy, FAD), ectoparasites, etc |
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interface dermatitis
a. what is it b. causes c. lesions |
a. inflammatory cells (cytotoxic T cells) target basal keratinocytes --> basal keratinocyte degeneration (ballooning change) & individual cell death (apoptosis)
mediated by lymphocytes cell rich type: cytotoxic T cells target basal keratinocytes cell poor type: chronic dermal ischemia --> basal cell death b. most are autoimmune Lupus tissue rxns: discoid lupus, systemic lupus erythema multiforme complex: drug rxns, post infection? chronic ischemic dermatopathies: dermatomyositis, rabies vaccine assoc. alopecia, chronic vasculitis of varied causes VKH-like syndrome: targets mostly melanocytes some epidermal viral infections c. shallow ulcers & erosions, depigmentation, vesicles when severe basal cell death (rare), epidermal atrophy (chronic nasal planum lesions) |
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vasculitis
a. what is it b. causes c. sites commonly affected |
a. inflammation targets vessels w/ damage to vessel walls (necrosis, fibrin deposition, hemorrhage)
b. tick borne dz (RSMF, etc.), sepsis, drug rxns, systemic lupus, equine purpura hemorrhagica, hypersensitivity (rare) c. ear tips/margins, footpads, oral cavity, scrotum, pressure points, tail tip |
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nodular & diffuse dermatitis
a. what is it b. causes |
a. inflammatory cells form nodules which may coalesce to produce diffuse infiltrates
b. R/O infectious causes 1st: remember to CULTURE! bacterial: Mycobacteria, Nocardia, Actinomyces fungal: Blasto, Crypto foreign body rxns Oomycetes: Pythium, Lagendium neoplasms can also present as nodules & masses |
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intraepidermal vesicular & pustular dermatitis
a. what is it b. causes |
a. intraepidermal structures break down --> acantholysis --> formation of intraepidermal vesicles, bullae, &/or pustules
acantholysis: keratinocytes separate & become more round than normal b. superficial bacterial pyoderma/impetigo pemphigus foliaceus pemphigus vulgaris: uncommon dermatophytosis: uncommon presentation early stages of some viral infections: often progress quickly to erosions or ulcers |
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subepidermal vesicular & pustular dermatitis
a. what is it b. causes |
a. subepidermal (basement membrane) structures break down --> separation of epidermis from dermis --> subepidermal vesicles, bullae, &/or pustules
b. autoimmune blistering dz (middle aged animals): autoAb target BM proteins; bullous pemphigoid, mucus membrane pemphigoid, epidermolysis bullosa aquisita hereditary blistering dz (young animals): genetic defect in a protein in BM; dystrophic epidermolysis bullosa, junctional epidermolysis bullosa |
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perifolliculitis, folliculitis, furunculosis
a. what are they b. causes c. lesions |
a. perifolliculitis: inflammatory cells accumulate in dermis around hair follicle but do not enter
folliculitis: inflammatory cells infiltrate epithelial wall &/or lumen of hair follicle furunculosis: rupture of hair follicle, usually in assoc. w/ folliculitis b. bacteria (Strep intermedius), dermatophytosis, Demodex c. papules &/or nodules |
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panniculitis
a. what is it b. causes |
a. inflammatory cells infiltrate pannicular septa (CT) &/or lobules of fat
b. assume infectious until proven otherwise --> tx w/ AB’s 1st other: idiopathic sterile nodular panniculitis pancreatitis or pancreatic neoplasia: release of pancreatic enzymes --> fat breakdown --> inflammation (rare) post injection panniculitis: focal rxn d/t vaccine administration, some drugs |
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atrophic dermatitis
a. what is it b. causes |
a. atrophic changes in hair follicles (--> alopecia) & less often in dermis & epidermis
NOT an inflammatory lesion b. endocrinopathies (ex. Cushing's, steroid administration, hypothyroidism, sex hormone related) chronic ishemic dermatopathies: dermatomyositis, rabies vax assoc. panniculitis & alopecia |
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What are hemidesmosomes?
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connect epidermal basal keratinocytes to BM, which connects to dermal collagen
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What is the epidermal basement membrane?
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sheet-like meshwork of proteins that connects epidermis to dermis
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epidermis
a. layers b. cell types |
a.stratum corneum, stratum granulosum, stratum spinosum, stratum basale
b. keratinocytes (~85%), melanocytes, Langerhans cells (skin MPs), lymphocytes (few migrating thru) |
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What are keratin intermediate filaments?
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connect keratinocytes together via desmosomes in cell mem: meshwork that holds cells together
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acquired skin fragility
a. species affected b. cause |
a. cat
b. 2º to steroid tx (atrophy of dermal collagen), Cushing’s (rare) |
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solar injury
a. results of sustained solar injury b. what is solar keratosis |
a. solar dermatitis (sun burn) --> solar keratosis --> SCC
b. ex. dog abdomen (epidermal hyperplasia & dysplasia, vascular injury to superficial dermis) |
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photosensitization
a. primary b. secondary c. pathogenesis |
a. preformed photodynamic agent ingested (ex. plants) or administered (drugs)
b. hepatic dz impairs excretion of phylloerythrin, a product of chlorophyll formed in GI tract c. photodynamic agent (chromophore) circulates to skin --> sun actives agent --> reactive oxygen intermediates --> superficial vascular & skin necrosis --> ulcers & crusting of white, sun exposed areas |
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What are some skin diseases that are exacerbated by sun exposure?
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pemphigus foliaceus
discoid lupus erythematosis vesicular cutaneous lupus |
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superficial pyoderma
a. part of skin involved b. lesions c. examples |
a. epidermis & upper infundibulum of hair follicles
b. erythema, alopecia, papules, pustules, crusts, epidermal collarettes c. superficial pustular dermatitis (impetigo), superficial spreading pyoderma, Dermatophilosis, greasy pig dz (exudative epidermitits) |
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deep pyoderma
a. part of skin involved b. example |
a. hair follicle, dermis, &/or subcutis
b. staphylococcal folliculitis & furunculosis |
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dermatophytosis
a. part of skin involved b. lesions |
a. infect & grow in cornified layers (keratophilic): stratum corneum, hair shafts, occ. claws
b. circular areas of alopecia, scaling, papules w/ folliculitis, sometimes nodules (kerion) d/t coalescing rupture of hair follicles (furunculosis) |
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feline ulcerative facial dermatitis & stomatitis
a. etiology b. lesions |
a. feline herpesvirus
b. asymmetrical alopecia, often assoc. w/ mucus membranes |
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demodicosis
a. etiologic agent b. part of skin infected c. 2 forms d. dx |
a. Demodex canis
b. lives in follicle lumen (most normal dogs have some mites) c. localized: small patches of alopecia generalized: 5 or more localized regions or over whole body -may be d/t immunosuppression in adults -susceptible to bacterial infection --> generalized pustular demodicosis d. hair plucking, deep skin scrape |
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scabies
a. etiologic agent b. part of skin infected c. lesions |
a. Sarcoptes scabei
b. lives in epidermis: tunnels & deposits eggs --> epidermal hyperplasia (lichenification) c. small # of mites --> severe lesions d/t self trauma, hypersensitivity (extremely pruritic) |
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What are the 2 things that must happen for a hypersensitization rxn to occur?
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1st: sensitization phase to an allergen
2nd: elicitation phase after subsequent allergen challenge = exaggerated immune response assoc. w/ clinical signs |
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pemphigus foliaceus
a. pathogenesis b. distribution of lesions |
a. autoAbs disrupt attachments (desmosomes) b'twn keratinocytes (acantholysis)
b. symmetric lesions on face, ears, footpads often see crusting d/t drying up of pustules |
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pemphigus vulgaris
a. pathogenesis b. distribution of lesions |
a. acantholysis right above basal cell layers --> deep erosions, ulcers
b. oral cavity |
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Name 3 autoimmune skin diseases that target the BM & describe the distribution of lesions for each.
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bullous pemphigoid
-distribution: skin, oral cavity, ears -lesions: deep erosions, ulcers mucus membrane pemphigoid -distribution: mucocutaneous junctions (nose, eyes, oral cavity, genitalia) epidermolysis bullosa acquisita -distribution: skin, foot pads -lesions: vesicles & bullae |
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VKH-like syndrome
a. pathogenesis b. lesions |
a. lymphocytes target melanocytes
b. periocular & nasal depigmentation, uveitis --> blindness |
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What skin lesions are associated w/ Cushing's?
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truncal alopecia, comedones, scaling, dry hair coat, variable thinning of skin, often 2º bacterial pyoderma, hyper- or hypo- pigmentation
dogs: calcinosis cutis horses: hirsutism |
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canine zinc responsive dermatosis: syndrome I
a. signalment b. cause c. lesions |
a. Siberian Huskies, Alaskan Malamutes
b. defect in Zn absorption --> diffuse parakeratosis: retention of nuclei in stratum corneum c. scale, hyperkeratosis, crusting on face, pressure points, foot pads, ear tips, around eyes, eyes mouth |
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canine zinc responsive dermatosis: syndrome II
a. signalment b. causes c. lesions |
a. puppies, esp. large breed
b. relative zinc deficiency, rapidly growing animals; low zinc, high calcium, &/or high phytates c. scale, hyperkeratosis, crusting on face, pressure points, foot pads, ear tips, around eyes, eyes mouth |
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primary seborrhea
a. primary lesion & cause b. dx c. sequelae |
a. defect of keratinization --> scaling (hyperkeratosis): may be dry or oily
b. idiopathic: dx of exclusion (uncommon) c. secondary bacterial infection |
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secondary seborrhea
a. primary lesion b. causes c. sequelae |
a. primarily epidermal hyperplasia, NOT epidermal
hyperkeratosis b. occurs 2º to some other inflammatory problem in skin (common) c. secondary bacterial infection |
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sebaceous adenitis
a. pathogenesis b. signalment c. lesions |
a. proposed keratinization defect or immune mediated
b. standard poodles, vizslas, Samoyeds, akitas, chows c. inflammation targets sebaceous glands --> lots of scaling +/- significant alopecia |
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What are some causes of hyperkeratosis of the nasal planum & footpads in dogs?
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distemper (hard pad dz), pemphigus foliaceus (hyperkeratosis, crusting from pustules), zinc responsive dermatosis, idiopathic or familial in some dogs, hepatocutaneous syndrome (hyperkeratosis, crusting)
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pancreatic paraneoplastic syndrome
a. species affected b. cutaneous lesions c. non-cutaneous lesions |
a. cat
b. shiny skin, ventral alopecia, fissures & redness on paws c. anorexia, cachexia, lethargy, abdominal distension |
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exfoliative dermatitis & thymoma
a. cutaneous lesions b. non-cutaneous lesions |
a. lymphocytes target epidermis --> redness, scaling, patchy alopecia of head, neck, ears
b. coughing, respiratory distress, anorexia, muscle wasting |
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hepatocutaneous syndrome
a. cause b. lesions c. sequelae |
a. severe liver dz
b. scaling, crusting: usually symmetrical c. 2º infection common: bacteria, Candida, Malasezzia |
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pancreatic panniculitis (necrotizing panniculitis, pansteatitis)
a. species affected b. causes c. lesion |
a. cat
b. pancreatic neoplasia, nutrition possible (↑ unsaturated fatty acids in diet, ↓ Vit. E) c. fat necrosis --> inflammation (steatitis) |
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cutaneous hemangioma/HSA
a. may be associated w/? b. layers of skin affected |
a. may be solar associated on ventral abdomen of thin haired dogs
b. deep into panniculus, skeletal muscle or can be very superficial |
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cutaneous melanomas: locations & assoc. behavior
a. dogs b. gray horses |
a. most on haired skin are benign, those on claw bed or in oral cavity are often malignant
b. perineal, tail, prepuce --> lymph node, systemic involvement (slowly progressive) |
