There are a number of different types of tongue coating and the most common is usually not a cause for any concern. It is a result of food particles, bacteria and saliva accumulating between the papillae of the tongue but can be easily removed with proper brushing. However, sometimes white coatings in the mouth may be a disease that cannot be removed and requires medical treatment.
What is oral leukoplakia?
Oral leukoplakia are white patches or plaques that appear on the inside of the mouth (oral mucosa). It cannot be rubbed or scraped off and may be precancerous (early signs of cancer) or potentially cancerous. However, most of the time these lesions are benign (non-cancerous) and therefore not serious. The exact cause of leukoplakia is unknown but is closely associated with tobacco use. Another similar condition known as hairy leukoplakia is associated with EBV (Epstein-Barr virus) infection.
It affects less than 1 out 100 people and is more common among men than women. Oral leukoplakia mainly occurs after the age of 40 years. The risk of oral leukoplakia lesions being pre-cancerous ranges from 0.6% to 20% based on the results of various studies. It can be removed by physical scraping with a scalpel, laser or freezing if stopping tobacco does not lead to resolution of the lesions.
Causes of Oral Leukoplakia
The inner lining of the mouth is known as the oral mucosa. It covers the gums, inner cheeks, inner lips, roof of the mouth (palate), tongue and under the tongue. The mucosa is continuous with the throat. In oral leukoplakia, the affected parts of the oral mucosa are abnormally thickened. When the epithelial cells of the oral mucosa appear abnormal in shape, size and other characteristics as would be expected then it may be indicative of a pre-cancerous lesion.
The exact cause of oral leukoplakia is unknown. It is associated with tobacco use, both chewed and smoked, and is usually seen in long term tobacco use. It is believed that this link may be due to chronic irritation of the mucosa by tobacco and tobacco smoke. However, tobacco is not the only link that has been observed. Habitual alcohol use, poorly fitting dentures, oral candidiasis, glossitis (tongue inflammation) due to syphilis and certain vitamin deficiencies may also be associated with oral leukoplakia.
Signs and Symptoms
Oral leukoplakia appears as white to gray patches or plaques that are irregularly shaped and are either flat or slightly raised. Some lesions may be thick and hard. There is usually no pain or any other symptoms and smaller patches may often go unnoticed. Many people may try to brush or scrape it off on their own but to no avail. Sometime these lesions may also be accompanied by redness of the underlying and surrounding oral mucosa.
Although oral leukoplakia can occur anywhere on the oral mucosa, the most commonly affected sites are:
- Under the tongue
- Side of the tongue
- Floor of the mouth
- Soft palate
- Lower lip
There are two types of oral leukoplakia that may be observed:
- Homogenous oral leukoplakia lesions are uniformly flat and white in color with a thin appearance. These lesions less likely to be pre-cancerous.
- Non-homogenous oral leukoplakia lesions are irregular in color (white to white-red) or in texture (flat, nodular, speckled or verrucous). These lesions are more likely to be pre-cancerous.
Oral Leukoplakia and Mouth Cancer
Oral leukoplakia is the most common type of lesion seen preceding mouth cancer. This does not mean that every person who has oral leukoplakia will develop mouth cancer. In fact, the majority of people with oral leukoplakia have benign (non-cancerous) lesions and it will not progress to a malignancy (cancer). Similarly not every person who has mouth cancer has oral leukoplakia initially.
Mouth cancer following oral leukoplakia appearance is more likely with the non-homogenous form. During the early stages of mouth cancer associated with oral leukoplakia, there may be no significant changes or alteration in appearance of the oral leukoplakia lesions. Therefore every person with oral leukoplakia should have the lesions monitored on an ongoing basis. The presence of bleeding, ulceration (open sores), protruding masses or hard masses are more likely to be associated with a malignancy (cancer). Pain may be absent in the early stages of mouth cancer.
Diagnosis of Oral Leukoplakia
Oral leukoplakia is diagnosed with a biopsy (collection of tissue sample) and examination of the sample. This is done in a laboratory. However, it may not be immediately done. Initially a doctor may recommend a change in lifestyle habits, like new brushing routines and quitting tobacco use as well as treatment of underlying infection like oral thrush (candidiasis). If this fails to yield any results then a biopsy is done.
Treatment of Oral Leukoplakia
Treatment is only considered when other measures to attend to the underlying cause and lifestyle changes fails to resolve the lesions. It should only be done once a diagnosis of oral leukoplakia is confirmed. In order to remove the plaque it is scraped by one of the following methods:
- Manually with a scalpel.
- Cryotherapy (freezing).
- Laser ablation.
If the following treatments fail, then ongoing assessment by an otorhinolaryngologist (ENT specialist) is advisable to consider other approaches to treating the condition as well as for ongoing monitoring to detect oral cancer as early as possible.
Prevention and Lifestyle
Oral leukoplakia cannot always be prevented. For underlying conditions like oral thrush (candidiasis), proper medical treatment of these conditions can reduce the chance of oral leukoplakia forming. Preventative measures should be targeted at lifestyle habits since these are the most likely causes or triggers of oral leukoplakia. This includes:
- Stop using all tobacco products. This includes tobacco smoking and chewing.
- Reduce alcohol intake or stop it altogether. The risk of oral leukoplakia increases in smokers who also consume alcohol.
- Seek immediate correction for poorly fitting dentures.
- Avoid repeatedly scraping the lesions with a brush or other object. It contributes to the repeated irritation of the area.
- Have regular dental checkups to ensure that new oral leukoplakia lesions are not developing as well as to monitor existing lesions.