Dermatology Flashcards
What type of sensitivity reaction is contact dermatitis?
Typer 4 hypersensitivity
What is the cause of seborrheic dermatitis?
Pityrosporum ovale
What is seborrheic dermatitis
Infants: severe, red diaper rash or thick crust on scalp
Children/adults: red, scaly patches seen around the eyes, ears, nasolabial fold, mid chest, and scalp
Auspitz sign
bleeding when scale is scropped (associated with psoriasis)
What type of hypersensitivity is hives?
Type 1
When do drug eruptions usually occur? (i.e how many days after taking the drug?)
7-14 days (so if a patient reacts wtihin 1-2 days, it is probably not the drug causing it!
Stevens Johnsons Syndrome
Epidermal separation involving <10% of body surface area
Toxic epidermal necrolysis
Epidermal separation of >30% of BSA
Nikolsky’s sign
Separation of superficial skin layers with slight rubbing (think about SJS and TEN!)
What else is on the differential with SJS and TEN?
SSSS (which is usually seen in kids < 6yo and has infectious etiology
Erythema nodosum
Painful, erythematous nodules on the lower legs and slowly spread. Fom infection, drugs, inflammatory disease
Infections causing erythema nodosum
Streptococcus, coccidioides, yersinia, TB)
Inflammatory diseases causing erythema nodosum
sarcoidosis, Crohn’s disease, UC, Behcet’s disease
Anatomic location of bullous pemphigoide vs. pemphigus vulgaris
BP: basement membrane
PV: intraepidermal
anti-desmoglein
In pemphigus vulgaris
Nikolsky’s sign of bullous pemphigoide vs. pemphigus vulgaris
BP: negative
PV: positive
Severity of bullous pemphigoide vs. pemphigus vulgaris
BP: milder
PV: possible death
Who is molluscum contagiosum common in?
young children and AIDS patients
What is the cause of impetigo
GAS and staphylococcal organisms
cause of necrotizing fasciitis
s. pyogenes or mixed infection (s. aureus, e.coli, clostridium perfringens)
What tests must be done monthly for a patient on accutane?
beta-hCG, LFTs, cholesterol, and triglycerides
Pilonidal cyst
Abscesses in the sacrococcygeal region
What is the cause of tinea versicolor?
Malassezia furfur!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Gangrene
Necrosis of body tissue
Dry gangrene
Due to insufficient blood flow to tissue
Wet gangrene
Involves bacterial infection, usually with skin flora
Gas gangrene
C perfringens infection
Lichen planus
Planar, purple, pruiritic, persistent, polygonal, penile, perioral, puzzling
What virus is associated with pityriasis rosea?
HHV 6 or 7
Seborrheic keratosis
NO MALIGNANT POTENTIAL; STUCK ON APPEARANCE
Stuck on appearancw
Seborrheic keratosis
Actinic keratosis
Precurosr of SCC
What skin cancer commonly occurs on the lip?
SCC
what is the cause of kaposi’s sarcoma?
HHV-8
