Severe cutaneous adverse reactions due to isoniazid in a HIV positive patient.

Severe Cutaneous Adverse Reaction (SCAR) represents the spectrum of adverse drug reactions from erythema multiforme, Stevens - Johnson syndrome (SJS) to Toxic Epidermal Necrolysis (TEN). A 55 year old lady presented in a toxic state with peeling of skin, blisters on the body of seven days duration following medications taken for fever and pulmonary tuberculosis. When referred to our institution, she was diagnosed as TEN. Immediately the suspected medications were stopped. The essential investigations were done including the screening for immunosuppression, which was found to be negative. The patient was treated symptomatically with emphasis on skilled nursing care. The patient's skin condition improved gradually but tuberculosis progressively worsened over three months. Thus patient was reinvestigated for seropositivity and was found to be positive. Considering the benefit - risk ratio along with the advice of the pulmonologist, a decision was made to give her a rechallenge test, first for antitubercular drugs and later for antipyretics. The patient developed SJS within two days of starting isoniazid (INH). On withdrawal of INH the patient recovered.