Rapid oral desensitization to isoniazid and rifampin.

A 45-year-old black woman, sputum positive for acid-fast bacilli, developed hypersensitivity to both isoniazid and rifampin. She was admitted to the hospital and desensitized to both medications using modified penicillin protocols. Skin testing was negative to both drugs. Desensitization to isoniazid was complicated by a drug fever that was controlled by prednisone. The patient was able to maintain once-a-day dosing without incident even with steroid taper. To our knowledge, this is the first reported case of dual isoniazid and rifampin hypersensitivity with rapid oral desensitization.