Inflammation of the tongue. It is characterized by swelling and a smooth appearance with possible tenderness and impaired speech, swallowing, and mastication. The whole surface of the tongue may appear smooth (atrophic glossitis) if all the filiform and sometimes the fungiform papillae are lost. Benign migratory glossitis see tongue, geographic. Median rhomboid glossitis is characterized by an asymptomatic smooth red nodular rhomboidal-shaped lesion located on the dorsum of the tongue in the midline, anterior to the circumvallate papillae; it is thought to be caused by a localized candidal infection. Glossitis can be due to a large number of causes including bacterial or viral infection, mechanical trauma (e.g. sharp teeth, restorations or appliances), burns, irritation from alcohol or tobacco, or allergic reactions. The tongue appears pale if it is caused by pernicious anaemia and fiery red if caused by vitamin B deficiency. See also tongue, geographic.