Derm Dx: Black, velvety coating of the tongue

A patient, aged 61 years, was referred because of the recent onset of darkening on the surface of his tongue. He denied pain and stated that his sense of taste was unaffected.

The patient was on an antihypertensive medication and two weeks earlier had been started on oral doxycycline for rosacea. He denied taking bismuth-containing over-the-counter compounds and did ...