Keratin is constantly produced by the dorsal tongue papillae, and in the normal situation, the rate at which the keratin is produced is equal to the rate at which it is debrided by normal mechanical actions of chewing and swallowing foods. Anything that disturbs that balance will result in coated or hairy tongue:
- Increased production of keratin can be seen with any irritant, including cigarette smoking, continuous exposure to hot beverages, or excessive brushing of the dorsal tongue.
- Antibiotics, corticosteroids, and antipsychotics are the most common triggering medications.
- Decreased debridement is seen in patients who are edentulous (or have complete dentures) or have chronic hyposalivation for any reason, either of which can cause the patient to select a soft or more liquid diet.
- Patients who have a chronic illness that results in decreased food intake frequently develop a coated or hairy tongue as well.