A 23-year-old male complains of recurrent scaly lesions on glans penis. It always occurred at the same site and healed with slight hyperpigmentation. What is the most likely diagnosis?

Ans. a. Fixed drug eruption (Ref: Roxburgh's 17/e p95; Fitzpatrick 7/e p359-60; Bahl 9/e p270)The most likely diagnosis in a 23-year-old male complaining of recurrent scaly lesions on glans penis, occurring at the same site and healed with slight hyperpigmentation is fixed drug eruption.Fixed Drug EruptionAdverse cutaneous drug reaction appearing soon after ingestionQ (from 30 min to 8 hours) of offending agent in previously sensitized individuals.Drugs Implicated in Fixed Drug Eruption* PhenolpthaleinQ (present in some laxatives)* BarbituratesQ* MetronidazoleQ* FluoroquinolonesQ* SulphonamidesQ (Cotrimoxazole, dapsone)* TertracyclineQ* Salicylates and phenacetinQCharacteristic Features:Mucocutaneous junction (lip, glans) is most frequently involved, genital skin (glans) is the most commonly involved siteQ.Most commonly lesions are solitaryQ but they may be multiple.Lesions evolve from macules to papules to vesicles and bullae then erodeQ.Lesions heal by hyperpigmentationQUsually asymptomaticQ but may be pruritic, painful, or burning (when eroded)Lesions persist if the drug is continued and resolve days to weeks after drag is continuedFDE occurs repeatedly at the same (i.e. fixed) site within hours, every time drug is taken and heals by residual grayish or slate colored hyperpigmentationQDiagnosis:Diagnosis is confirmed by provocation.Rechallenging the patient to the suspected offending drug is the only known test to possibly discern the causative agent.Treatment:The main goal of treatment is to identify the causative agent and avoid it.Symptomatic treatment: Systemic antihistamines and topical corticosteroids may be all that are required.