MTB - Dermatology Flashcards
ab’s to intercellular space of epidermal cells
pemphigus vulgaris
causes of pemphigus vulgaris:
idiopathic
ACE inhibitors
Penicillamine
3 diseases that have positive Nikolsky’s sign
pemphigus vulgaris
TEN
SSSS
are the lesions in pemphigus painful or pruritic?
painful
most accurate dx test - pemphigus vulgaris
biopsy of the skin
DOC: pemphigus vulgaris
glucocorticoids - prednisone
what drugs can be used in pemphigus if steroids are ineffective?
azathioprine
mycophenolate
cyclophosphamide
dz characterized by tense bullae formation, usually in an elderly person
bullous pemphigoid
Dx. test - bullous pemphigoid
biopsy w/ immunofluorescent abs
Tx. bullous pemphigoid
systemic steroids (prednisone)
alternatives:
- tetracycline
-erythromycin w/ nicotinamide
Pemphigus Foliaceus
blistering dz assoc with other autoimmune diseases or drugs (ACE inhibitors or NSAIDs); much more superficial than pemphigus
a patient presents with nonhealing blisters on sun-exposed parts of the body, hyperpigmentation of the skin and hypertrichosis of the face - dx?
porphyria cutanea tarda
- abnormal photosensitivity reaction
porphyria cutanea tarda is associated with…
alcoholism liver disease hep C OCP use liver dz - chronic hepatitis, hemochromatosis diabetes
Dx test - porphyria cutanea tarda
urinary uroporphyrins
Tx. porphyria cutanea tarda
- stop drinking alcohol
- stop estrogen use
- use barrier sun protection
- use phlebotomy or deferoxamine
- chloroquine (increases excretion of porphyrins)
uriticaria
hypersensitivity reaction mediated by IgE and mast cell activation resulting in wheals and hives and pruritus.
Medications causing uriticaria
aspirin NSAIDs morphine/codeine penicillins phenytoin quinolones
MCC of uriticaria
medications insect bites foods emotions contact w/ latex
Management - uriticaria
severe and acute? first generation anti-histamines
chronic? newer gen, nonsedating anti-histamines
morbilliform rash
typical type of drug reaction - generalized maculopapular eruption that blanches with pressure; mediated by lymphocytes
tx. morbilliform rash
antihistamines
causes of erythema multiforme
penicillins phenytoin NSAIDs sulfa drugs infection w/ herpes simplex or mycoplasma
describe erythema multiforme
targetlike lesions esp. on palms and soles; does not involve mucosal membranes
Tx. erythema multiforme
antihistamines
Stevens-Johnson syndrome
Hypersensitivity reaction involving < 10-15% of BSA and mucous membrane involvement (oral cavity and conjunctivae)
What meds can cause SJS?
penicillins sulfa drugs NSAIDs phenytoin phenobarbital
Management of SJS
pts should be managed in burn unit (high risk for infection, dehydration and malnutrition)
meds to try: IVIG, cyclophosphamide, cyclosporine, thalidomide
Toxic Epidermal Necrolysis
most serious version of cutaneous hypersensitivity
- involves from 30-100% of BSA w/ mortality of 40-50% (MCC of death is due to sepsis)
Dx. TEN
skin biopsy
fixed drug reaction
localized allergic drug reaction that recurs at precisely the same anatomic site on skin w/ repeated drug exposure leaving a hyperpigmented, sharply demarcated spot
tx. fixed drug reaction
topical steroids