Riboflavin (vitamin B2) deficiency, also called ariboflavinosis, is extremely rare in the United States. Besides low intake, causes can include thyroid hormone insufficiency and some diseases. People who are low in riboflavin are usually low in other nutrients too, so some signs may reflect those other deficiencies.
Common symptoms
Cracks or sores at the corners of the mouth (angular stomatitis)
Swollen, cracked lips (cheilosis)
Redness and swelling of the mouth and throat; sore throat
Skin disorders
Itchy, red eyes
Hair loss
Anemia and cataracts when deficiency is severe and prolonged
At-risk groups
Vegetarian athletes, especially those who avoid milk, yogurt, cheese and eggs
Pregnant and breastfeeding women who rarely eat meat or dairy, and their infants
Vegans and people who consume little milk
People with riboflavin transporter deficiency, a rare inherited neurological disorder
When to see a doctorPersistent cracks at the corners of the mouth, a sore swollen mouth or throat, or itchy red eyes can have many causes, including low intake of several B vitamins. A doctor or dietitian can assess your diet and decide whether testing is needed.