INH-induced pellagra

History

          A very interesting case of pellagra localized to the exposed parts of the hands only. The patient was diagnosed as pulmonary tuberculosis and started anti-Tb therapy (Rifampicin+INH+ETB). Three months later she suffered well-circumscribed red scaly hyperpigmented rash on the back of both hands whereas other photosensitive areas were not affected. The rash had been diagnosed as eczematous and there was no response to topical corticosteroids for 6 weeks. On multivitamine supplemental therapy containing nicotinic acid 100 mg three times daily the rash improved dramatically within one week. The treating physician was asked to modify the anti-Tb therapy regarding INH which is the most probable cause of pellagroid rash.