Hairy leukoplakia manifests as a leathery white callus on the side of the tongue. Like common leukoplakia , it is not easily scraped off. Unlike leukoplakia, it is NOT caused by chronic exposure to noxious chemical exposure like tobacco smoke or chronic mechanical abrasion. It is caused by the Epstein-Barr virus which often hides out in the body without causing overt symptoms. Epstein-Barr is an opportunistic viral parasite which causes symptoms when the body’s own immune system is at a low ebb. The most frequent disease associated with the Epstein-Barr virus is mononucleosis.
When HIV first entered the public consciousness, dentists were taught that the appearance of white hairy tongue was “Pathognomonic” of HIV which means that the presence of this particular sign meant that that patient had HIV beyond any doubt. Over time, we discovered (often the hard way) that this is NOT the case. However, it is still a sugestive sign, and whenever I see a patient with white hairy tongue, I ask the patient if he or she has AIDS or has recently been tested for HIV. I then recommend that the patient be tested for their own safety and health.