Black hairy tongue with a fixed dose combination of olanzapine and fluoxetine

Black hairy tongue (BHT) is a benign disease characterized by elongated filiform lingual papillae, with a carpet-like appearance of the dorsum of the tongue. It is has been reported to occur with a prevalence ranging from 0.6% to 11.3%. Although its etiology is not fully understood, BHT may be triggered by smoking, excessive coffee or black tea drinking, poor oral hygiene, trigeminal neuralgia, general debilitation, dry mouth as well as certain drugs. We present here a case of a patient with psychosis, depression, and benign prostatic hyperplasia, who developed BHT following treatment with a fixed dose combination (FDC) of olanzapine and fluoxetine and recovered within 3 months after withdrawal of treatment with FDC.