Isonicotinic acid hydrazide induced anagen effluvium and associated lichenoid eruption

A 32 year-old woman developed generalised lichenoid eruptions on her body followed by diffuse loss of scalp hair of the anagen effluvium type. She was receiving several anti-tubercular drugs, including rifampicin, isonicotinic acid hydrazide (INH), pyrazinamide, and ethambutol, for abdominal tuberculosis. INH, which is a leading cause of drug eruptions in the above group of drugs was withdrawn. However, the other antitubercular drugs were continued along with 40 mg of prednisolone in a single daily morning dose. The latter was discontinued slowly over a period of 10 weeks. There was complete recovery of hair loss and the regrowth started after 12 weeks of alopecia. Such anagen effluvium with lichenoid eruption following INH therapy has not been observed previously. The complete recovery from anagen effluvium is difficult to explain, but it could have been because of the early initiation of corticosteroid.