Geographic tongue, also known by several other terms, is a condition of the mucous membrane of the tongue, usually on the dorsal surface. It is a common condition, affecting approximately 2–3% of the general population. It is characterized by areas of smooth, red depapillation (loss of lingual papillae) which migrate over time. The name comes from the map-like appearance of the tongue, with the patches resembling the islands of an archipelago. The cause is unknown, but the condition is entirely benign (importantly, it does not represent oral cancer), and there is no curative treatment. Uncommonly, geographic tongue may cause a burning sensation on the tongue, for which various treatments have been described with little formal evidence of efficacy. Signs and symptoms
In health, the dorsal surface of the tongue is covered in tuft-like projections called lingual papillae (some of which are associated with taste buds), which give the tongue an irregular surface texture and a white-pink color. Geographic tongue is characterized by areas of atrophy and depapillation (loss of papillae), leaving an erythematous (darker red) and smoother surface than the unaffected areas. The depapillated areas are usually well-demarcated, and bordered by a slightly raised, white, yellow or grey, serpiginous (snaking) peripheral zone. A lesion of geographic tongue may start as a white patch before the depapillation occurs. In certain cases there may be only one lesion, but this is uncommon; the lesions will typically occur in multiple locations on the tongue and coalesce over time to form the typical map-like appearance.
Beside the differences in locations of presentation inside the oral cavity and prevalence among the general population, in all other aspects of clinical significance, symptoms, treatment, and histopathologic appearance, these two forms are identical. This condition is sometimes termed (oral) erythema migrans, but this has no relation to the more common use of the term erythema migrans (erythema chronicum migrans), to describe the appearance of skin lesions in Lyme disease and southern tick-associated rash illness. Treatment
Geographic tongue (GT) also termed benign migratory glossitis usually presents without symptoms and due to a lack of reliable evidence, researchers can not identify a specific treatment for the condition. It is currently suggested that patients are given reassurance that the condition is entirely benign and self-resolving. Although there is no established gold standard treatment confirmed by current evidence, patients with symptomatic GT can be advised on several treatment options prescribed by the clinician on a case-by-case basis. This includes possible prescriptions of antihistamines, anxiolytics, corticosteroids and topical anaesthetics. It is recommended that patients avoid spicy and acidic foods. Research has not shown high levels of evidence for the treatment of symptomatic GT and larger study sizes are needed to come to a reliable recommendation. Prognosis
The condition may disappear over time, but it is impossible to predict if or when this may happen. Epidemiology
Geographic tongue is a common condition, affecting 2-3% of the adult general population, although other sources report a prevalence of up to 14%. It is one of the most common tongue disorders that occurs in children.