Sexually active male comes with complaints of recurrent ulcers over the glans which heals with hyperpigmentation . Lesions characteristically recur after intake of sulfonamidees, probable diagnosis is -: (A) Aphathous ulcer, (B) fixed drug eruption, (C) Herpes genitalis, (D) Chlamydial infection
Answer is B. Fixed drug eruption It characteristically recur at the same site following administration of offending drugs or occasionally a member of the same group of drugs. They occur 30min to 8hrs after drug administration Most common drugs: Sulfonamides NSAIDS Dapsone Batbiturates Ciprofloxacin Phenytoin Griseofulvin Metronidazole Antituberculous drugs Pathomechanism Drug induced CD8 positive Tcells induce INFs and TNFalpha dependent damage to keratinocytes Clinical features Single / multiple, round / oval lesions Well demarcated erythematous edematous plaques that resolve with violaceous /hyperpigmented macules Associated burning/ stinging and pruritus Most common sites: oral mucosa; glans penis; hands and feet Bulbous fed: generalised well defines erythematous and bulbous lesions bilateral and symmetrical. Pseudoephedrine causes nonpigmented FDE lesion heal without pigmentation Investigations: oral or topical provocation test. Test drug is taken orally or applied topically Treatment Discontinue the offending drug Coicosteroids: topical and systemic Antihistamines IADVL textbook of dermatology page 1668