Riboflavin (vitamin B2) deficiency, also called ariboflavinosis, is extremely rare in the US but can occur in people with very limited diets, alcohol use disorder, or specific genetic disorders. Riboflavin deficiency rarely occurs alone — it usually appears alongside deficiencies of other B vitamins.
Common symptoms
Cracks at the corners of the mouth (angular stomatitis)
Swollen, cracked lips (cheilosis)
Sore throat
Magenta-colored, swollen tongue (glossitis)
Skin disorders, including seborrheic dermatitis around the nose and mouth
Itchy, red, or bloodshot eyes; sensitivity to light
Hair loss
Fatigue from associated normocytic anemia
At-risk groups
People with alcohol use disorder (poor intake plus impaired absorption)
People with very limited diets or anorexia
Strict vegans avoiding all dairy and fortified foods (dairy is a major source)
Pregnant and breastfeeding women with poor intake
Adolescents during growth spurts who skip breakfast
Athletes with extremely high energy expenditure and poor diet
People with malabsorption conditions
People with rare inherited disorders affecting riboflavin transport
When to see a doctorPersistent cracks at the corners of the mouth, recurrent sore throat with swollen tongue, or seborrheic dermatitis that doesn't respond to standard treatment may warrant evaluation for B-vitamin deficiencies. A dietitian or doctor can assess intake and order targeted testing.