Matthys: Intro to Dermatology Flashcards
Macule
-Flat spot on skin measuring <1cm
Patch
> 1 cm
Papule
-nonpustular, nonvesicular lesion on skin <1 cm
Nodule
> 1cm
Vesicle
-small blisters <1 cm
Bulla
> 1 cm
Pustule
-a collection of leukocytes in the epidermis
Plaque
-broad, elevated flat lesions > 1cm
If there is an erythematous lesion that is non scaling, what could it be?
- if localized with sepsis: cellulitis
- localized w/o sepsis: insect bites, acne, hemangioma
- generalized systemic signs: urticaria, EN, Viral exanthems, annular erythemas
If there is an erythematous lesion that is scaling, what could it be?
- if papulosquamous: pityriasis, psoriasis, tinea corporis, syphillis…
- if eczematous: atopic dermatitis, contact dermatitis, scabies…
clinical findings of atopic dermatitis
- Xerosis and icthyosis vulgaris
- pigmentary changes
- eye and periorbital changes
- hand and foot dermatitis (allergic salute)
differential dx with atopic dermatitis
- allergic contact dermatitis
- seborrheic dermatitis
- tinea infection
- nummular eczema
tx for atopic dermatitis
- moisturize
- avoid irritants
- avoid known food allergies
- topical and oral antipruritic agents
- anti-inflammatory agents
cellulitis
- acute, rapidly spreading nonsupprative infection of the skin and underlying soft tissue NOT including the muscle
- Erysipelas is more superficial than cellulitis
clinical findings in cellulitis
- tender, warm, poorly demarcated boggy plaque
- commonly on an extremity
- trauma
pathogenesis of cellulitis
- trauma to an extremity either known or unknown
- concurrent ulcer
Risk factors for cellulitis
- stasis dermatitis
- lymphedema
ddx for cellulitis
- venous thrombosis
- gout
- lipodermatosclerosis
- chronic stasis dermatitis
Tx for cellulitis
- becuase it’s usually due to staph aureus or strep pyogenes, just use first gen cephalosporin, macrolide, or clindamycin
- elevation
Erythema nodosum
- 20-30
- symmetric erythematous nodules and plaques located on the anterior lower extremities
clinical findings for EN
- tender nodules and plaques on the bilateral knees, ankles, and shins
- sometimes thighs and upper extremity
- one to 15 cm in size
- rarely ulcerate
what causes EN?
- hypersensitivity things
- he said birth control was a big one
- septal panniculitis is ddx
- sarcoidosis
tx for EN
-anti inflammatory and rest
What is the koebner phenomenon?
-re create psoriasis by trauma… not contagious
What is the auspitz sign?
-peel away the psoriatic scale and get pinpoint bleeding
What is Woronoff’s ring?
-when you get rid of psoriasis and it leaves behind a pigmented ring
different types of psoriasis?
- plaque type
- pustular
- Guttate
Plaque type psoriasis
- well demarcated scaly plaque
- elbows, knees, belly button
- coin shaped
- annular pattern
- thick
Histology of psoriasis
- acanthotic epidermis with club shaped rete ridges and an absent granular layer
- tortuous vessels seen in the papillary dermis
ddx for psoriasis
- seborrheic dermatitis
- nummular eczema
if there is a coin shaped lesion with a thin plaque, what is that?
-nummular eczema
pustular psoriasis
- sterile sheets of pustules on an erythematous base
- localized or generalized
- painful with fever
- guy who looked like he had a shit ton of zits
ddx for pustular psoriasis
- AGEP
- Drug eruption
- Subcorneal pustular dermatosis
Guttate
- children and young adults
- post strep infection
- some predisposition to psoriasis
- trunk with sparing of palms and soles
guttate ddx
- secondary syphillis (contagious)
- pityriasis rosea
Herpes Zoster
- reactivated varicella zoster virus
- immunocompromised
clinical findings for herpes zoster
- local radicular pain 2-3 days prior to the eruption
- disseminated zoster
- herpes zoster ophthalmicus
- postherpetic neuralgia
what will we see on pathology for herpes zoster?
- steel gray nuclei
- multinucleated giant cells with eosinophilic intranuclear inclusions
ddx of herpes zoster
- chicken pox
- atypical measles
- cellulitis
Tx for Herpes Zoster
- antivirals
- contagious; can cause chickenpox
- pain control
- vaccine at age 60
