Black hairy tongue — elongated hyperkeratotic filiform papillae with dark pigmentation.

Black hairy tongue Hairy tongue results from defective desquamation and hypertrophy of the filiform papillae, allowing chromogenic bacteria and food debris to accumulate. Triggers include antibiotics, smoking, poor oral hygiene, coffee/tea, and oxidizing mouth rinses. Candidiasis is wipeable and white. Leukoplakia is white and cannot be rubbed off; it is not described as "hairy" or black.