This often results in a depapilled, atrophic glossitis, giving the tongue a bald and shiny appearance, along with pallor (paleness) of the lips and other mucous membranes a tendency towards recurrent oral ulceration, and cheilosis (swelling of the lips). The appearance of the tongue in iron deficiency anemia has been described as diffuse or patchy atrophy with tenderness or burning. One cause of iron deficiency anemia is sideropenic dysphagia (Plummer–Vinson or Paterson–Brown–Kelly syndrome) which is also characterized by esophageal webbing and dysphagia.Pernicious anemia is usually caused by autoimmune destruction of gastric parietal cells. Parietal cells secrete intrinsic factor which is required for the absorption of vitamin B12. Vitamin B12 deficiency results in megaloblastic anemia and may present as glossitis. The appearance of the tongue in vitamin B12 deficiency is described as "beefy"
or "fiery red and sore". There may be linear or patchy red lesions. Vitamin B deficiencies
Vitamin B1 deficiency (thiamine deficiency) can cause glossitis. Vitamin B2 deficiency (ariboflavinosis) can cause glossitis, along with angular cheilitis, cheilosis, peripheral neuropathy and other signs and symptoms. The glossitis in vitamin B2 deficiency is described as magenta. Vitamin B3 deficiency (pellagra) can cause glossitis. Vitamin B6 deficiency (pyridoxine deficiency) can cause glossitis, along with  angular cheilitis, cheilosis, peripheral neuropathy and seborrheic dermatitis. Folate deficiency (vitamin B9 deficiency) can cause glossitis, along with macrocytic anemia, thrombocytopenia, leukopenia, diarrhea, fatigue and possibly neurological signs. Apart from pernicious anemia discussed above, any other cause of vitamin B12 deficiency can cause glossitis, which tends to be painful, smooth and shiny.
It may be primary, where there is no underlying cause, or secondary where it is a sign or symptom of another condition. It can be acute or chronic. Generally speaking, there are several clinical patterns of glossitis, some more common than others. Atrophic glossitis
Atrophic glossitis, also known as bald tongue, smooth tongue, Hunter glossitis, Moeller glossitis, or Möller-Hunter glossitis, is a condition characterized by a smooth glossy tongue that is often tender/painful, caused by complete atrophy of the lingual papillae (depapillation). The dorsal tongue surface may be affected totally, or in patches, and may be associated with a burning sensation, pain and/or erythema. Atrophic glossitis is a non-specific finding, and has a great many causes, usually related to iron-deficiency anemia, pernicious anemia, B vitamin complex deficiencies, unrecognized and untreated celiac disease (which often presents without gastrointestinal symptoms), or other factors such as xerostomia (dry mouth). Although the terms Möller and Hunter glossitis were originally used to refer to specifically the glossitis that occurs in vitamin B12 deficiency secondary to pernicious anemia, they are now used as synonyms for atrophic glossitis generally. In this article, the term glossitis, unless otherwise specified, refers to atrophic glossitis. Candidiasis may be a concurrent finding or an alternative cause of erythema, burning, and atrophy. Median rhomboid glossitis
This condition is characterized by a persistent erythematous, rhomboidal depapillated lesion in the central area of the dorsum of the tongue, just in front of the circumvallate papillae. Median rhomboid glossitis is a type of oral candidiasis, and rarely causes any symptoms.