Atrophic glossitis is a term describing the atrophic changes of the tongue that is principally seen in various nutritional deficiencies. The term "smooth tongue" is used to illustrate its appearance, and pain, as well as several other features, may be present depending on the etiology. A detailed clinical assessment and a thorough laboratory workup is necessary to identify the underlying cause.
Atrophic glossitis (AG) is a disorder of the tongue mucosa characterized by atrophy of the filiform papillae (and fungiform according to some authors) on the dorsal surface of the tongue    . As a result, ulcer-like lesions on the dorsal and lateral tongue appear, and the term "smooth" or "bald" tongue is used to describe the smooth and glossy red-to-pink mucosa   . AG is typically seen in adults and elderly individuals, and the most common causes are nutritional deficiencies, (iron, vitamin B12, folic acid, riboflavin, and niacin) and protein malnutrition     . In this patient population, pain and a burning sensation of the tongue are frequently reported . In addition to nutritional deficiencies, a number of diseases have been confirmed as possible causes of AG, including amyloidosis, Sjögren syndrome, sarcoidosis, infections (candidiasis, syphilis), bullous dermatoses (pemphigus, bullous pemphigoid), alcohol abuse, exposure to chemical irritants and numerous drugs    . Celiac disease, however, a gluten-sensitive enteropathy, is one of the more important causes of AG, in which case chronic diarrhea, vomiting, weight loss, and growth impairment accompany the changes seen on the tongue . Conversely, anemia is a frequent finding in AG due to iron (sideropenic) or vitamin B12 deficiencies (pernicious anemia). Thus symptoms of weakness and fatigue may be present as well  .
The diagnosis of atrophic glossitis mandates a thorough clinical and laboratory workup in order to identify the underlying cause, as the list of diseases that can induce atrophic changes is quite long . The distinct red-to-pink and smooth appearance of the tongue and the presence of erythematous and sharply defined ulcer-like lesions should be easily recognized during the physical examination, suggesting that the role of a proper exam is perhaps crucial in making the initial diagnosis. In addition, a comprehensive history taking is equally important, as it may identify additional complaints, assess if preexisting disorders might cause tongue-related symptoms, determine whether proper dietary intake of nutrients is normal (as malnutrition is a common etiology, especially among the elderly), and exclude alcohol abuse . Once the clinical diagnosis of AG is made, the physician should order a full laboratory workup comprising of a complete blood count (CBC) that often reveals anemia, serum levels of iron, ferritin and total iron binding capacity (TIBC), folic acid, several B group vitamins, gastric parietal cell antibodies, and also homocysteine levels, which could also contribute to atrophy of the tongue  . If there is a suspicion of celiac disease then, IgA-endomysial, tissue transglutaminase, and antigliadin antibodies should be tested .