Exam 3 chronic skin infections Flashcards
Describe clinical features of psoriasis
sharply demarcated erythema usually with thick micaceous scale, auspitz sign, koebner phenomenon
Describe the histopathology of psoriasis
Extensive hyperkeratosis and parakeratosis, uniform elongation of the rate ridges, neutrophils swarm to epidermis
Pathogenesis of psoriasis
T cell mediated autoimmune disorder: T cells produce cytokines that stimulate keratinocyte proliferation
What other things can psoriasis be confused with, how do you differentiate?
Lichen simplex chronicus, nummular eczema, seborrheic dermatitis, tinea corporis; punch biopsy
Common areas of psoriasis
elbows, knees, presacral, nails, palms and soles
What are the 4 different kinds of psoriasis?
Chronic plaque, inverse (fold areas, only erythema), guttate (after strep, tear drop shaped scaled spots), pustular (small pustules becoming generalized with fever)
Treatment of psoriasis
topical agents (steroids, retinoids), Systemic (retinoids, cyclosporin, UVB/narrow band, methotrexate)
What is the main complication of psoriasis
psoriatic arthritis
Describe the hallmarks of lichen planus
6 P’s: planar, purple, polygonal, pruritic, papules, plaques
How do you diagnose lichen planus?
punch biopsy
What is lichen planus often associated with?
Hepatitis C
What is the classical form of lichen planus? Describe
Linear lichen planus; erythematous to violaceous polygonal papules in the flexor ares (wrist and ankles), Wickham’s striae (white patter in mouth)
Describe the forms of lichen planus
Hypertrophic: very thick plaques over lichen planus.
Bullous: blisters that occur under lichen planus (interface dermatitis)
Scalp: lichen planopilaris-scarring alopecia of scalp
What is the treatment of lichen planus
may resolve spontaneously in 1-2 years, topical steroids, oral steroids, phototherapy STOP THE DRUG IF IT INDUCED IT
What kinds of drugs can induce lichen planus?
thiazide, sulfa related, beta blockers, captopril
What is the classic sign of acute lupus erythematosus
butterfly rash across the nose and the cheeks, photosensitive pattern of erythema, joint pain as well
What are the three types of lupus erythematosus
Acute (pauci-inflammatory interface dermatitis), Subacute (prominent suprabasilar exocytosis of lymphocytes), Discoid (very thick basement membrane)
What is the most important lab test for lupus erythematosus? Others?
anti-nuclear antibodies; complete blood count, sed rate, liver/kidney tests, UA
What are the risk factors of SLE?
women>men, ages 14-40, more common in african-americans, hispanics, asians
Treatment of SLE?
NSAIDs, antimalarials, corticosteroids, immunosuppresants (cyclophosphamide, azathaprine)
What triggers SLE
Sunlight, medications (anti-seizure, antibiotics, BP rx)
What are some non-specific skin lesions associated with lupus?
Talangiectasia vasculitis, thrombophlebitis, Reynaud’s; Alopecia, urticaria, mucous membrane, pigment changes
