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41 Cards in this Set
- Front
- Back
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What are the common skin diseases? |
Psoriasis, seborrehic dermatitis, eczema/dermatitis, acne vulgaris, cutaneous drug reations
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What are the types of secondary skin lesions? |
Scale - flakes of compated stratum corneum. Crust - dried exudate on skin. Artophy - thinning of skin/subcuntaneous fat. Lichenification - thickening of epidermis due to rubbing. Erosion - depressed area of skin with epidermis loss. Exoriation - skin abrasion by rubbing. Fissure - linear leavage into dermis. Scar - permanent fibrosis due to dermal damage. Eschar - overlying dark hard cover on ulcer indicating necrosis/gangrene. Keloids - exaggerated connective tissue response beyond edge of injury |
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What is the prevalence and risk of psoriasis?
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~3% of the population (1 million Canadians). High rate in Caucasians. Even gender split. Common onset young adults. Inherited susceptibility (1 in 3 people have affected relative) |
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How is psoriasis autoimmune mediated?
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Skin is 'non-self'. Dendritic cells & T-cells. Migrate from dermis to epidermis. Cytokine release - inflammatory reponse, keratinocytes proliferate. |
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What are the precipitating factors for psoriasis?
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Skin injury, discontinuation of systemic corticosteroids, cold water, streptococcal throat infections, emotional stress, alcohol, smoking, HIV, medications - beta blockers, ACE inhibitors, lithium, antimalarial drugs |
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What are complications of psoriasis?
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Increased risk for myocardial infarction (7x increase). Depression. Psoriatic arthritis - 30% of patients. |
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What are the classifications of psoriasis?
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Pustular - raised noninfectious pustules; surrounding skin is red, tender, inflammed; localized or generalized.
Nonpustular - most common; papules -> plaques; well defined, raised, red plaques, scales are silver/white |
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What are the diagnostics of psoriasis?
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Auspitz sign - punctate bleeding spots when scale is scratched off.
Candle sign - scratched edges of scales should be 'greasy'.
Sign of last hautchen - lesion is dry to final layer |
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Where are the lesions found?
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Scalp, elbows, legs, knees, nails, lower back, palms/soles, buttocks
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What are the three classifications of psoriasis?
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Mild - only a few patches, less than 3% of the skin surface.
Moderate - 3% - 10% of the skin surface.
Severe - more than 10% of the skin surface. |
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What is the pathology of psoriasis?
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Keratinocyte proliferation. Hyperkeratosis - thickening of the epidermis. Dilated blood vessels. Elongation of rete pegs - epithelial extensions into connective tissue under skin. |
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What are the types of psoriasis?
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Psoriasis vulgaris - annular/limpet like. Guttate psoriasis - small scaly papules. Erythrodermic psoriasis - generalized form. Pustular psoriasis - noninfectious pustules. |
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What is the prevalence and risk of seborrheoic dermatitis?
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Common, chronic inflammatory dermatitis, 1-5% of the population. Affects all ages, affects more males than females. In regions with many sebaceous (oil) glands - face, scalp, behind ears, upper trunk, skin folds. Hereditary - positive family history. |
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What is seborrheoic dermatitis linked to?
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Linked to yeast infection - sp Malassezia. Believed to release lipid metabolites that inflame/irritate the skin, particularly on the scalp. Some individuals have increased oil production. |
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What are the risk factors?
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Illness, stress, fatigue, reduced general health, low humidity, cold temperatures.
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What are drug triggers of SD?
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Cimetidine, lithium, methyldopa, buspirone, ethionamide, haloperidol, phenothiazines.
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Describe SD.
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Lesions - pink to red, superficial, itchy patches/plaques, yellow-red-brown, flaky, occasionally greasy scale. Can attach to hair shaft. Dandruff is common on scalp. |
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What is eczema/dermatitis?
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Eczema = dermatitis. Involves both the epidermis and dermis.
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What are the two classes of eczema?
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Acute eczema - itchy, red, papulovesicular, crusted. Chronic eczema - itchy, leathery hypertrophied dry scales. Dry skin. Lichenification. |
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What are the two classes of dermatitis?
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Atopic and Contact
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What is atopic dermatitis?
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React abnormally and easily to irritants. Begins in childhood <5. Common - places of flexion. Inherited predisposition - increased risk of allergic reactions, asthma. Increase in IgE production. *Itching leads to rashing.* Increased risk of infection. |
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What is contact dermatitis?
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Allergic/irritant contact dermatitis - inflammation due to contact with substance; large, burning rashes, itchy. Chemical irritants - lead to necrosis in area of exposure - phenols, organic solvents, alkali hydroxides. Allergic stimulus via Hypersensitivity IV - CD4+ T cell activation, spread to surrounding tissue, includes drug-induced reactions. -Poison oak. -Poison ivy. |
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What is acne vulgaris?
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Chronic inflammation - Pilosebaceous unit - hair follicle, sebaceous gland, arrector pili muscle.
Common - with puberty (70-90%), diminishes by 25, more males affected, genetic component, face, shoulders, back, chest. |
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What are the precipitating/risk factors for acne vulgaris?
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Hormones - androgens increase during puberty in both genders, anabolic steroids, steroids, progestins. Family history. Stress. Tropical climate. Cosmetics. Environment - diet & exposure. Drugs - phenytoin, phenobarbital, lithium. |
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What are the types of follicle blockages?
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Comedones - blackhead. Papules. Pustules. Nodules/cysts. Scars. |
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What does the pathophysiology of AV involve?
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Hyperkeratosis - follicular epidermal hyperproliferation (leads to clumping of keratinocytes plugging hair follicle). Excess sebum production - oil glands increase size and production; sebum - oily/waxy matter lubricate and waterproof the skin, becomes trapped, solidifies behind keratin plug. Bacterial growth and colonization - Propionibacterium acnes proliferation and activity, P. acnes oil metabolism to fatty acids, fatty acids induce inflammation. |
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Describe non-inflammatory acne vulgaris.
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Closed and open comedones.
Closed comedones (1-2mm) - whiteheads, first clinical sigh, high tendency to rupture.
Open comedones (2-5mm) - blackheads, visible keratin plug, oxidized melanin and oil = black colour, stable. |
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Describe inflammatory acne vulgaris.
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Papulopustular/nodular lesions. Deep pimples. PRISH. |
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What are the types of cutaneous drug reactions?
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Maculopapular rash. Urticaria/andioedema. Fixed drug eruption. Steven-Johnson's syndrome (SJS) - toxic epidermal necrolysis (TEN) |
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What is a maculopapular rash?
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95% of cutaneous drug reactions. Flat, red area on the skin that is covered with small confluent bumps. Papules/macules - red, symmetric, occationally itchy. Begin on body truck - peripheral spread to extremitites. |
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What is the time course for Maculopapular Rash?
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~1 week of starting therapy, 7-14 day duration.
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What are the common drug reactions causing MR?
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Penicillins/cephalosporins, sulfonamides, allopurinol, anticonvulsants |
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What is the morphology of urticaria?
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Hives, itchy, red wheals of varying size, can lead to cardiorespiratoy failure.
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What is the morphology of angioedema?
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Swelling, dermal and subcutaneous fluid retention. Impact respiratory and GI mucous membranes. Can cause anaphylactic shock. |
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How does does urticaria/angioedema last?
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<24 hours |
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What are the common drug reactions causing U/A?
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ACE inhibitors, penicillins, aspirin, ibuprofen
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What are fixed drug eruptions?
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Systemic and intermittent exposure to a drug.
Macule - one or more well defined, can develop plaque, burning sensation.
Acute inflammatory response - can lead to hyperpigmentation.
Localized - to fixed (same) location. |
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What are the common drugs causing fixed drug reactions?
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Penicillins, tetracycline, sulfonamides, barbituates, phenolphthalein, gold salts.
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What is SJS/TEN?
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SJS is a milder form of TEN.
Delayed hypersenstivity reaction - T lymphocyte mediated.
Rare life-threatening ~30% mortality. |
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What is the disease progression for SJS/TEN?
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~1 week after medication onset. 1-2 week fever.
Symptoms of upper resp tract infection (pain, sore throat, conjunctivitis).
Macules/bullae/ulcers and desquamation on mucosal membranes and skin.
T-cell mediated death and release of keratinocytes |
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What are the drugs causing SJS/TEN? |
Sulfonamides, carbamazepine, ethosuximide, ethosuximide, lamotringe, phenobarbital, phenytoin |
