Coated tongue

History

          A middle-aged woman presented with an asymptomatic off-white creamy coat covered the dorsal surface of the tongue of two weeks duration. Her history was negative except for recently taken oral metronidazole. On stoppage of suspected culprit (Flagyl) the crust had disappeared within 7-10 days. On rechallenging with metronidazole the coat has appeared again. Smear and culture from the coat was negative for candida.