Vitamin B2, also known as riboflavin, is a water-soluble vitamin found in meats, fish, eggs, milk, green vegetables, yeast, and enriched foods. This vitamin is an essential co-enzyme for the metabolism of fat, carbohydrates, and protein. Vitamin B2 also plays a role in steroid metabolism.

Deficiency is more common than appreciated, and vitamin B2 deficiency may coexist with other B vitamin deficiencies due to overall inadequate nutritional status. Vitamin B2 deficiency manifests with mucocutaneous findings. The characteristic oculo-orogenital syndrome is associated with vitamin B2 deficiency, along with vitamin B6 deficiency. Laboratory work may reveal a normocytic anemia.

Individuals with a restricted diet, anorexia nervosa, and those with malabsorption syndromes are at increased risk of developing riboflavin deficiency. Those who avoid dairy products or who have celiac disease, short bowel syndrome, or anorexia nervosa are also more likely to have riboflavin deficiency.

Neonatal deficiency can occur secondary to maternal deficiency during pregnancy or be associated with phototherapy for jaundice.