drug rxns and blistering Flashcards
three most important types of drug rxns
exanthematous (95%), Drug related eosinophilia with systemic symproms (DRESS), SJS-TEN
can you do allergy testing for drugs?
only penicillin
Drug initiation is usually ___days before exanthematous rash appears. In DRESS (DIHS)
7-10. 3 weeks
name two dz states which have high drug reactivity
EBV and aminopenicillins. HIV and sulfonamides
describe measles rash
“morbilliform”. Spreads like can of paint poured on head.
what do you do when a pt presents with facial edema and rash?
Order CBC and LFTs to see it is systemic
Drug induced hypersensitivity sydrome or DRESS: systemic or local? other signs? How long after starting meds?
systemic with skin eruption and internal organ involvement. Exanthem, swelling, EOSINOPHILIA. 3 Weeks
How does resolution of exanthematous compare to DRESS?
exanthematous resolves in days. DRESS may persist
Three classic drugs implicated in DRESS
allopurinol, sulfonamide, phenytoin (anticonvulsant0
Treatment for DRESS
topical steroids or if severe, systemic steroids (prednisone)
Target lesions, esp on hands and face. Associated with? Can it progress to TEN?
Erythema multiforme. preceding HSV or Mcoplasma infection. No progression
Distinguish Stevens-Johnson from Toxic Epidermal Necrolysis. What do the lesions look like?
SJS 30%. Dusky red to purpuric. Atypical targets with dark center
What is the dz process in the epidermal necrolysis dzs?
extensive keratinocyte apoptosis due to Fas-FasL
Drugs implicated in SJS/TEN
Sulfa antibiotics, Anticonvulsants, tetracyclines, allopurinol, NSAIDS
Blisters/erosions on elbows and buttocks. Gluten allergy
dermatitis herpetiformis
