Geographic tongue (also known as benign migratory glossitis and erythema migrans) is a descriptive term applied to a map-like appearance of the tongue resulting from irregular exposed patches on its surface.
The healthy tongue is a mass of muscle fibers covered by a mucous membrane. On the underside of the tongue the mucous membrane is smooth. On the upper side the tongue is covered with many tiny protrusions called papillae. These papillae come in four types with different shapes. Three of these types contain taste buds; the fourth does not. The fourth type is called filiform papillae and they are packed tightly together over the entire upper surface of the tongue.
In geographic tongue the filiform papillae are missing in the reddish areas and are overcrowded in the gray-white borders.
We still do not know exactly what causes geographic tongue but we do know that it strongly tends to run in families and has polygenic inheritance. It is associated with several different genes.
Geographic tongue is also significantly more common in people who are sensitive to the environment i.e. those with allergies eczema and/or asthma. It is also four times more common in those with diabetes. Other causes may include local irritation of a small portion of the tongue from hot or spicy foods alcohol tobacco or other local irritants.
The pattern on the surface of the tongue may change very rapidly. The pattern results from the loss of tongue papillae (tiny finger-like projections on the surface of the tongue) giving areas of the tongue flat spots and the subsequent geographic appearance. These areas of papillae loss are called denuded areas and may persist for more than a month. Occasionally mild irritation of the tongue is reported.
The symptoms of geographic tongue are very easy to spot and include:map-like appearance to the surface of the tongue patches and lesions on the tongue that can appear beefy red smooth and feel sore location of lesions changing from day to day
Examination of the tongue is usually sufficient to make the diagnosis. No tests are usually necessary.
To avoid geographic tongue it is best to avoid local irritation (hot/spicy food alcohol tobacco and so on) if you are prone to geographic tongue.
Geographic tongue heals spontaneously. The individual lesions often heal at the same time new ones are forming changing the appearance of the tongue over hours or days. This gives rise to the appearance that the map is migrating across the face of the tongue. Thus geographic tongue is also called benign migratory glossitis. Although benign this condition may last for months and often recurs.
No treatment is normally needed but anti-fungal and antibacterial medications may be used for symptomatic cases.