<unk>  is the medical condition caused by deficiency of riboflavin (vitamin B2).<unk>  is most often seen in association with protein-energy malnutrition, and also in cases of alcoholism.
It was originally known as pellagra sin pellagra, as it exhibits certain similarities to the niacin deficiency pellagra. The most common cause of riboflavin deficiency is an inadequate diet, thus it occurs most frequently in populations consuming limited quantities of riboflavin-containing foods such as meats, eggs, milk, cheese, yogurt, leafy green vegetables and whole grains. Riboflavin deficiency can also occur in those with impaired liver function, which prevents proper utilization of the vitamin. Borderline riboflavin deficiency as a consequence of certain anti-retroviral medications has also been known to cause acute lactic acidosis.
The signs and symptoms of riboflavin deficiency typically include sore throat with redness and swelling of the mouth and throat mucosa, cheilosis and angular stomatitis (cracking of the lips and corners of the mouth), glossitis (magenta tongue with atrophy), seborrheic dermatitis or pseudo-syphilis (moist, scaly skin particularly affecting the scrotum or labia majora and the nasolabial folds), and a decreased red blood cell count with normal cell size and hemoglobin content (normochromic normocytic anemia).
Riboflavin deficiency is usually found together with other nutrient deficiencies, particularly of the other water-soluble vitamins. Phototherapy to treat jaundice in infants can cause increased degradation of riboflavin, leading to deficiency if not monitored closely. Persons with chronic alcoholism can have impaired absorption of riboflavin and other vitamins such as thiamine (see Wernicke's encephalopathy).
Studies of the Turkoman people of Iran, who have a significantly increased incidence of esophageal cancer, have shown some relationship between chronic riboflavin deficiency and the onset of esophageal malignancies. One study of pregnant women has found that riboflavin-deficient women were 4.7 times more likely to develop preeclampsia, though the mechanism for this is not known.
The US Recommended Daily Allowance (RDA) for riboflavin ranges from 1.1 to 1.3 milligrams per day for healthy adults to as high as 1.6 mg/day for pregnant or nursing women.
Ariboflavinosis
Lead poisoning
Gold poisoning
Mercury poisoning
Histidinemia
Acatalasemia
Methemoglobinemia
Isovaleric acidemia