11. Dermatology Flashcards
Impetigo
- tx
- what if pen allergix
amox/1st gen cephalosporin
clinda
Acne tx approach
pyramid:
refractorry: isoreitinoin (get UPreg)
severe: Doxy/Erythromycin
inflamed pustulses: benzyoyl peroxide
comedones: retinoids, topical.
what 2 fungal infxns need oral tx?
- what if don’t tx?
- danger of orals?
Hair/Nails needs orals x several months:
- tinea capitis–griseofulvin
- onychomycosis–terbinafine
-permanent hair loss if don’t tx tinea capitis
long term oral can have hepatotox. Therefore, must confirm dx with KOH before starting oral tx
contact dermatitis:
2 forms
irritant and allergic
irritant: direct toxic chemical effect on skin (occupation related chemical)
allergic: nickel, poison ivy, latex, etc
what is stasis dermatitis
people with leg edema (venous insuff), get leg flaking, erythema, brown discoloration, scaling.
Don’t bx, as non-healing ulcer may occur. Venous stasis ulcer may also be present.
pemphigus vs pemphigoid
- sxs
- dx
- tx
- population
pemphigus: \+ nikolsky's, oral involvement bx shows tombstones steroids, MMF, Rituximab, life threatening Age 30-50
pemphigoid: - nikolsky's, no oral bx IF shows Ab to dermal-epidermal jxn Age 70-80 steroids
Bullous skin diseases (4 to know):
- pemphigus
- pemphigoid
- dermatitis herpetiformis
- porphyria cutanea tarda
porhyria cutanea tarda
- when to suspect
- how to dx
- tx
- when you see bullae on skin-exposed surfaces only
- Dark urine. Flouresces ‘coral red’ under Wood’s lamp. (urine uroporphyrins)
tx: avoid sun, Etoh , other triggers.
seborrheic dermatitis
- what is it
- tx
‘super-dandruff.’ (not seborrheic keratosis)
-cradle cap included
selenium shampoo
Psoriasis
-tx
1st step: UV light
topical steroids in flares
pityriasis rosea
- what is this
- what can it be confused with
- tx
- herald patch, progressing to salmon-colored lesions.
- can look like rash of syphilis. (syphilis has hands/soles, pityriasis does not)
- steroids, self limiting 6 weeks
drug rash
- how long after drug exposure
- appearance
- 4-14 days after exposure
- pink, morbilliform
Pt with target-shaped lesions on palms, soles.
Think what other than erythema multiforme?
Also, what are causes of erythema multiforme? (3)
-syphilis
- drug (esp cephalosporins)
- HSV
- mycoplasma
erythema multiforme/SJS/TEN
-what drugs can cause? (think 4 categories)
- sulfa
- PCN
- NSAIDs
- anticonvulsants
SJS vs TEN
-difference, how to know
2 things: body surface area, and Bx
SJS: <10% BSA, Bx shows basal cell degeneration
TEN: >30% BSA, full thickness necrosis
Bx also will find out SSSS
Pt with SJS/TEN: other than getting bx, do what (3)
- remove ALL meds, including steroids (can worsen!).
- Admit to burn unit
- give Clinda
SJS/TEN: how many days after drug exposure?
no correlation, could be days or weeks
melanoma
- mnemonic
- what to do if suspect?
ABCDE asymmetry border color DIAMETER >5mm evolution
Wide excisional bx, punch bx if on face and suspicion low
Seborrheic keratosis vs melanoma
seborrheic keratosis (stuck on age spots, look like ugly moles)
-if present long time, unchanged, it is SK. however, if new or changing, do bx to r/o melanoma.
actinic keratosis: what is dz spectrum?
-do what for actinic keratosis
actinic keratosis
Bowen’s dz (CIS)
SCC
pre-SCC, so do Bx. Do local ablation. If CIS/Bowen’s resect. Can also do 5-FU, imiquimod
Pt says they had “SCC that went away on its own” on his hand, think what
Keratoacanthoma. looks like SCC but grow and regress spontaneously.
If you see it, do resection like SCC
Pt with patchy depigmentation on skin:
- what dx to think:
- how to dx
- tx
- tinea versicolor.
-KOH prep–sphagethi meatballs
selenium shampoo. - vitiligo
- dx with Woods lamp
- steroids and UV light
Tuberous sclerosis:
-skin findings (3)
- shagreen patch (raised collagen)
- sebaceous adenomas (funny looking acne)
- ash-leaf macules (hypopigmented, use Woods lamp)
salmon colored rash, think what dx
-tx
pityriasis rosea
- always check RPR
- tx with topical steroids, 6 weeks self limiting
Patchy alopecia: dx approach?
Make sure exisiting hair same length (otherwise trich). Think tinea capitis–do KOH prep.
If KOH-, think lupus, get ANA.
Eczema
-first tx?
topical steroids (hydrocortisone)
benadryl is adjunct
Post-strep GN
-what is time frame after infection?
3-6 weeks after impetigo
1-2 weeks after strep pharyngitis
Hypersensitivity types 1-4?
- immediate Allergic reaction
- Ab target antigens on tissue surfaces. eg Graves, Myasthenia gravis, ABO incompat. no rashes.
- Ag/Ab complexes, depositing on tissues. eg RA, SLE, reactive arthritis
- delayed, T cells. eg contact dermatitis
key words:
- Ab against hemidesmosomes
- Ab against desmoglein
- neutrophilic abscess in dermal papillae
- pemphigoid
- pemphigus
- dermatitis herpetiformis
