Benign increase in the length of the filiform papillae (responsible for giving the tongue its texture and the sensation of touch) on the posterior dorsal aspect of the tongue, resulting in hair-like projection and a coated appearance. This is caused by an increased accumulation of keratin and/or diminished normal desquamation. It may be a result of a change in diet to insufficient coarse foods, often seen in hospitalised very ill patients, or related to salivary hypofunction caused by either systemic medications, Sjogren’s Syndrome or radiotherapy.
The colour of hairy tongue can vary substantially from deep black to white, and is dependent on both the resident bacteria and food debris.
On the posterior aspect of the dorsal surface of the tongue are quite extensive elongated filliform papillae, some of which are very darkly pigmented. These become more pronounced posteriorly. This patient had no symptoms.