Geographic tongue occurs when patches of the rough surface (papillae) of the tongue disappear, sometimes rapidly. The absence of papillae makes those parts of the tongue appear to look like a map, with smooth, bright red areas.

The cause of geographic tongue is not known, although it could be linked with allergies. In some cases geographic tongue causes soreness and burning. There is no specific treatment, although home treatment measures may relieve the soreness of geographic tongue. It may take a month for the tongue to regain its normal texture.