A 38 year old female patient was on Isoniazid therapy for tuberculosis. She developed rashes on the exposed pas of her body. She has disoriented memory. Family members gives history of diarrhea also. What is the diagnosis:: (A) Tuberculosis skin lesions, (B) Niacin deficiency, (C) Isoniazid neuropathy, (D) Some other drug has caused this
Answer is B. Isoniazid inhibits the endogenous synthesis of niacin. So the patient has developed pellagra i.e. dermatitis, dementia and diarrhea. Prolonged treatment with isoniazid leads to pyridoxine deficiency, which is required for endogenous synthesis of niacin.