The exact cause of leukoplakia is unknown but it may develop as a result of substances irritating the soft tissue inside the mouth.
In a few cases of leukoplakia, the cause is unknown (idiopathic).
Leukoplakia is most often linked to irritation of the mucous membranes (soft tissues) inside the mouth caused by the use of substances such as tobacco and alcohol.
Tobacco use is thought to significantly increase your risk of developing leukoplakia. People who smoke are considered to be more at risk of getting leukoplakia than those who don't.
The risk is higher for people who use smokeless tobacco products, such as chewing tobacco or betel nut preparations, such as paan. Studies have shown that regular users of betel nuts are 25 times more likely to develop leukoplakia than non-users.
Heavy alcohol use is also thought to significantly increase your chances of developing leukoplakia. Heavy drinkers are eight times more likely to develop leukoplakia than non-drinkers.
Heavy drinking is drinking more than the recommended daily limit for alcohol consumption, which is 3-4 units of alcohol for men and 2-3 units for women.
Binge drinking may also increase your risk of developing leukoplakia or mouth cancer.
Other possible causes of white patches
Other possible causes of white patches in the mouth that can be differentiated from leukoplakia include:
- frictional keratoses – this can be caused by misaligned teeth (malocclusion), ill-fitting dentures or long-term cheek biting
- oral lichen planus – a non-infectious rash that can sometimes occur in the mouth
- oral thrush (candidiasis) – a short-term fungal infection of the mouth
- a vitamin A or B deficiency
Oral thrush is caused by a group of yeasts called Candida. Leukoplakia associated with a candida infection is known as candidal leukoplakia.
Infection with the human papilloma virus (HPV) has also been suggested as a possible risk factor for leukoplakia. This link is currently being investigated.