By Disease Name > Fixed Drug Eruption

Fixed Drug Eruption

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common drugs = NSAID's, tetracyclines, sulfa drugs, phenopthalein

 

Clinical:

•glans penis is most common site
•usually develops within 30 minutes to 8 hours of drug administration
•sometimes blister (subepidermal)
•dusky in center because of necrosis
•patch test:
•at the fixed drug site – will reproduce the lesion
•another site – no reaction
•unclear pathogenesis

 

 

distinctive variant:

"Non-pigmenting Fixed Drug Eruption":

•most common drug = pseudoephedrine hydrochloride
•large, tender, often symmetrical erythematous plaques
•"baboon syndrome" = where buttocks, groin, and axillae are preferentially involved

 

 

 

histology:

•superficial and deep
•vacuolar alteration
•dyskeratotic keratinocytes
•ddx:  EM (histology = superficial), GVHD
•confident distinction among fixed drug, EM, and TEN based on biopsy alone, is not always possible