Derm Flashcards
What is the atopic triad
Asthma
Eczema
Allergic rhinitis
Contact dermatitis is what kind of reaction
Type iv hypersensitivity
“Linear” or “angular” rash often refers to
Contact dermatitis
Define papules
Elevated solid skin lesion <1cm
Plaque is a
Papule >1cm
Describe type I hypersensitivity reaction
First and fast (anaphylaxis, urticaria)
Antigen cross-links Ige on last cells and triggers release of histamines
What is serum sickness
Antibodies to the foreign proteins are produced in -5 days, immune complexes are deposited on membranes
Serum sickness is usually caused by
Drug reaction
Tb skin tests, transplant rejection and contact dermatitis are examples of ___ hypersensitivity
Delayed, type IV
Seborrheic dermatitis can be caused by a hypersensitivity reaction to
Malassezia furfur, a yeast
Cradle cap is due to
Seborrheic dermatitis
What am I? Severe red diaper rash with yellow scale, erosions and blisters
Seborrheic dermatitis
Tx of seborrheic dermatitis in adults
Selenium sulfide or zinc pyrithione shampoos
Baby with hx of eczema with new onset rash and fever and grouped vesicles in eczematous areas. What is it?
Eczema herpeticum, Medical emergency due to systemic spread of hsv infection
Tx of eczema herpeticum
Iv acyclovir
A rash involving extensor surfaces
Psoriasis
Rash involving flexor surfaces
Atopic dermatitis
What is auspitz sign
Classical presentation of psoriasis-pinpoint bleeding when scale is scraped
Drug reaction rashes usually occur how long after exposure
7-14 days
What kind of lesions do you see in erythema multiforme
Target lesions
Palms, soles and mucus membranes are often affected in
Erythema multiforme
Nikolsky sign in erythema multiforme is
Negative
If nikolsky sign is present, what two scary things should be on your differential
Sjs and ten
Biopsy of sjs shows
Degeneration of basal layer of epidermis
Biopsy in ten shows
Full thickness eosinophilic epidermal necrosis
Scalded skin syndrome is usually seen in____ and has an ___ etiology
Kids under six
Infectious
Sjs/ten is usually seen in ___ and is generally caused by ___
Adults
Drug reaction
Location of blisters in bullous pemphigoid
Basement membrane zone
Location of blisters in pemphigus vulgaris
Intraepidermal
Autoantibodies in bullous pemphigoid are directed against
Hemidesmosomal proteins
Autoantibodies in pemphigus vulgaris are directed against
Desmoglein responsible for keratinocyte adhesion
Nikolsky sign is ___ in bullous pemphigoid and ___ in pemphigus vulgaris
Negative
Positive
Pt age in bullous pemphigoid
> 60
Pt age in pemphigus vulgaris
40-60
Erosions are more common in bullous pemphigoid or pemphigus vulgaris
Pv
Tx of bullous pemphigoid
Steroids
Tx of pemphigus vulgaris
High dose steroids + immunomodulatory therapy
Dermatitis herpetiformis is associated with which dz
Celiac
Dx of herpes simplex lesion
Viral culture of lesion
If you have herpes what do you see on tzanck smear
Multinucleated giant cells
Molluscum contagiosum is what kind of virus
Pox virus
Tiny flesh colored dome shaped waxy papules with central umbilication. What am I
Molluscum contagiosum
Impetigo tx
Mild localized dz: topical abx like mupirocin
Severe non-Mrsa: cephalexin, dicloxacillin
Severe Mrsa: bactrim
Community acquired ___ is an increasingly common cause of cellulitis
Mrsa
Dysphasia, drooling, fever and red warm mouth. What am I?
Ludwig angina, a bilateral cellulitis
What is Fournier gangrene
A form of necrotizing fasciitis that is localized to genital and perineal area
A small red patch on a Child’s cheek or extremities that turns into a painful shiny plaque. What am I
Erysipelas, common causes by gas
Tx of erysipelas
Penicillin
Tinea versicolor is caused by
Malassezia furfur
Tx of tinea versicolor
Ketoconazole or selenium sulfide
Treatment of lice
Permethrin
Intense pruritus esp at night and after hot showers is characteristic of
Scabies
Scabies generally appears in ___ tracks
Linear, representing burrows of the mite
Which can be seen with the naked eye, lice or scabies?
Lice
Three subtypes of gangrene
Dry
Wet
Gas
Dry gangrene is due to
Insufficient blood flow to tissue usually from atherosclerosis
Wet gangrene is due to
Bacterial infection, usually with skin flora
Gas gangrene is due to
C perfringens infection
Demographic of pts with rosacea
Middle aged with fair skin more common in women
Tx of rosacea
Metronidazole
Which spares palms and soles, pityriasis rosea or secondary Syphillis
Pityriasis rosea
Initial treatment of dermatitis herpetiformis
Dapsone
Immediately after severe burns, infections tend to be caused by
Gram positives eg staph aureus
After 5 days post a severe burn, most infections are due to
Gram negatives (pseudomonas) or fungi
Right sided heart failure following an implantable pacemaker, think
Tricuspid regurg
Treatment of congenital long qt
Refraining from vigorous exercise, avoiding meds that can cause long qt, maintaining normal levels of calcium, potassium and magnesium
Beta blockers and pacemaker
What am I? Painful vesicles with an erythematous base that evolves to a punched out erosions with hemorrhagic crusting
Eczema herpeticum
Eczema herpeticum is due to what virus
Hsv1
What non-skin findings are associated with eczema herpeticum
Fever, irritability, lymphadenopathy
Tinea versicolor is caused by what bug
Malassezia globosa
Arterial ulcers occur where
Farthest distal places like tips of toes
What is a marjolin ulcer
Scc arising in a burn wound
Bright sharply demarcated erythema over perianal/perineal area in school aged children is likely
Perianal strep
Tinea capitis is most common in kids of what race
African American
Scaly, erythematous plaque on scalp that can progress to patchy alopecia plus lymphadenopathy
Tinea capitis
3 ds of pellagra
Dermatitis
Diarrhea
Dementia
In acute intermittent porphyria can you have diarrhea?
Yes
In acute intermittent porphyria are symptoms episodic or chronic
Episodic
Can pellagra by triggered by isoniazid
Yes
Can acute intermittent porphyria by triggered by isoniazid
Yes
What is a dermatofibroma
Common benign fibrous nodule on lower legs often hyperpigmented
See dimpling in the center when the area is pinched
What is congenital melanocytic Nevus
Benign proliferation of melanocytes usually forming solitary, hyperpigmented lesions with increased density of overlying dark coarse hairs
A furuncle is a
Hair follicle abscess
Tx of furuncle/folliculitis
Topical abx (mupirocin) for mild disease
More severe disease-treated like impetigo-oral cephalexin or cloxacillin
Is eczema itchy and scaly
Yes
Rash in someone on infliximab/generally immunocompromised? Think
Shingles
Tx of staph scalded skin syndrome
Nafcillin
Anaphylactic reaction mechanism
Antigen cross links igE on mast cells, releasing histamine
What is anaphylaxis
Hypotension in response to allergic reaction
What happens to hives when you push on them
They blanch
Immune response to sle and rheumatoid arthritis
Type iii, antigen-antibody immune complexes activate complement
Erythema multiforme is ___mediated, forming a ___ lesion and most commonly associated with
Immune complex
Targetoid lesion
Hsv
Tx of sunburn
Cool compresses, calamine lotion, NSAIDs
