[Research progress on the risk factors of geographic tongue]

Geographic tongue, also called benign migratory glossitis, is a common and superficial benign inflammatory disorder that affects the tongue epithelium. The majority of geographic tongue lesions typically manifest as irregular central erythematous patches. These lesions, which are caused by the loss of filiform papillae, are defined by an elevated whitish band-like border that can change location, size, and pattern over a period of time. Histological observations of the oral mucosa affected by geographic tongue revealed nonspecific inflammation. Some reports described cases of migratory stomatitis, wherein lesions simultaneously manifested on the extra lingual oral mucosa. This condition is also called ectopic geographic tongue, which is clinically and histologically similar to the type normally confined to the tongue. In most cases, patients are asymptomatic and do not require treatment. The condition may spontaneously exhibit periods of remission and exacerbation with good prognosis. The specific etiology of geographic tongue remains unknown. Geographic tongue is age-related and is prevalent among young individuals. Various etiological factors that have been suggested in literature include immunological factors, genetic factors, atopic or allergic tendency, emotional stress, tobacco consumption, hormonal disturbances, and zinc deficiency. Geographic tongue may coexist with other disorders, such as fissured tongue, psoriasis, diabetes mellitus, gastroin- testinal diseases, burning mouth syndrome, and Down syndrome. Experts currently disagree on whether geographic tongue is an oral manifestation of psoriasis. Moreover, some scholars suggest that geographic tongue is a prestage of fissured tongue. The objective of this review is to summarize current research on risk factors of geographic tongue.