derm Flashcards
what is the structure and function of the skin?
Barrier against fluid loss Protection from ultraviolet radiation Thermoregulation Cushioning Immunologic protection Appearance
Define macule
flat (nonpalpable), < 1cm in size
What is a patch?
flat (nonpalpable), > 1cm in size
What is a papule?
raised, < 1cm in size
What is a plaque?
raised (a broad papule), > 1cm in size
What is a nodule?
similar to a papule but > 1cm and located in the dermis or subcutaneous fat
What is a vesicle?
fluid filled, < 1cm in size
What is a bullae
fluid filled, > 1cm in size
What is a wheal?
(hive) – edematous papule or plaque that usually lasts < 24 hours
What is a scale?
dry or greasy laminated masses of keratin
What is crust?
dried serum, pus, or blood
What is a fissure?
a linear cleft through the epidermis or into the dermis
What is erosion?
loss of all or portions of the epidermis alone, heals without scarring
What is an ulcer?
complete loss of the epidermis and some portion of the dermis, heals with scarring
What is nummular dermatitis (etiology, age peaks)
“coin-shaped”
Etiology: unknown - classified as a form of atopic derm
2 peaks of age distribution - most common 6th to 7th decade of life M>F peak in 2nd to 3rd decade of life F>M
What is nummular dermatitis (presentation)?
round-to-oval crusted or scaly erythematous plaques
Most common arms and legs
Start as papules which coalesce into plaques with scale
Early lesions may be studded with vesicles containing serous exudate
Usually very pruritic
Often recurs in the same locations as old lesions
Lesions often symmetrically distributed
Waxes and wanes with winter
What is nummular dermatitis (ddx and treatment)?
DDx: contact derm, psoriasis, CTCL, pityriasis rosea, tinea corporis
Treatment: topical steroids, moisturization
Discuss topical steroids, use, risks, and recommendations
may alternate high potency with mid potency to reduce risk or use on weekends only
Risks of overuse of topical steroids include: atrophy, striae, telangiectasias, hypopigmentation (temporary), can have systemic absorption if using long-term on a large body surface area
Should recommend <14/28 days , 2-3 x week, Sat/ Sun use
classes (7) based on vasoconstrictive properties (ointment stronger than cream)
What are topical calcineurin inhibitors, when are they used, and where?
Topical calcineurin inhibitors (steroid sparing agents)
Tacrolimus (Protopic) ointment
Pimecrolimus (Elidel) cream
Discuss class 1 steroids and examples
superpotent
Clobetasol propionate
Betamethasone dipropionate
for scalp, palms, soles
Discuss class 3 and 4 steroids and examples
mid-strength Fluocinonide Betamethasone valerate Triamcinolone trunk and extremities
Discuss class 6 and 7 steroids and examples
Class 6 and 7= low potency Fluocinolone Desonide Hydrocortisone face, genitals, intertriginous areas
Discuss allergic contact derm, common culprits, and etiology
Etiology: delayed type of induced sensitivity - cutaneous contact with a specific allergen to which the patient has developed a specific sensitivity
~25 chemicals are responsible for as many as one half of all cases
Common culprits: Poison ivy, topical antibiotics (e.g., Neosporin, neomycin, bacitracin), nickel, rubber gloves, hair dye, textiles, preservatives, fragrances, benzocaine
Discuss allergic contact derm presentation and DDx
Presentation: pruritic papules and vesicles on an erythematous base
Acute onset
Geometric morphology (circles, lines, etc)
Lichenified pruritic plaques may indicate chronic ACD
Initial site of dermatitis often provides best clue regarding the potential cause
DDx: drug rash, nummular dermatitis, seb derm, tinea, urticaria