Geographic tongue

Geographic tongue, also known as benign migratory glossitis, erythema migrans, or continental tongue, is a condition affecting the tongue. The colloquial names are due to the condition resembling a map.

Symptoms
The top side of the tongue is covered in small protrusions called papillae. In a tongue affected by geographic tongue, there are red patches on the surface of the tongue bordered by grayish white. The papillae are missing from the reddish areas and overcrowded in the grayish white borders. The small patches may disappear and reappear in a short period of time (hours or days), and change in shape or size. While it is not common for the condition to cause pain, it may cause a burning or stinging sensation, especially after contact with certain foods, such as spicy or citrus foods. Chemicals, such as mouth washes and teeth whiteners, can also aggravate the condition. Geographic tongue may also cause numbness. Co-existence of fissures of the tongue is often noticed.

Histopathology
Irregular areas of dekeratinized and desquamated filiform papillae (red in color) are surrounded by elevated whitish/yellow margins due to acantholysis and hyperkeratosis. Neutrophils migrate into the epithelial layer, creating what are termed Munro's Abscesses.

Cause
Its cause is uncertain, though tends to run in families and is associated with several different genes. Geographic tongue is more commonly found in people who are affected by environmental sensitivity, such as allergies, eczema, and asthma. Some think that it may be linked to stress or diets high in sugar or processed foods. Its prevalence also varies by ethnicity (0.6% of Americans, 4% of young Iraqis, 2% of young Finns) and gender (females affected 3 times more than males).

Treatment
While there is no known cure or commonly prescribed treatment for geographic tongue, there are several ways to suppress the condition, including avoiding foods which exacerbate the problem. Some people affected by geographic tongue also report that taking Vitamin B supplements causes the condition to go away temporarily. Burning may also be reduced by taking antihistamines. The condition is usually asymptomatic and significant, persisting pain is rare. Geographic tongue is not associated with any known systemic diseases.

It has recently been found that geographic tongue can respond to zinc enhancements, such as Solvazinc®, taken orally. This opens up the question as to whether the condition is caused by an allergy or a deficiency.