DefinitionLeukoplakia is a precancerous sore (lesion) that develops on the tongue or the inside of the cheek in response to chronic irritation. Occasionally, leukoplakia patches develop on the external female genitals.Alternative NamesHairy leukoplakia; Smoker's keratosisCauses, incidence, and risk factorsLeukoplakia mainly affects the mucus membranes of the mouth. It is caused by irritation. Sores usually develop on the tongue, but they may also appear on the insides of the cheek.Irritation in the mouth may be caused by rough teeth or rough places on dentures, fillings, and crowns. It may also result from smoking or other tobacco use (smoker's keratosis). Persons who smoke pipes are at high risk for developing this condition, as are those who hold chewing tobacco or snuff in their mouth f