Nutritional supplements that may be helpful for seborrheic dermatitis

A group of researchers found that infants with cradle cap appeared to have an imbalance of essential fatty acids in their blood that returned to normal when their skin rashes eventually went away.³ In a preliminary trial, these researchers later found that application of 0.5 ml of borage oil twice daily to the affected skin resulted in clinical improvement of cradle cap within two weeks.⁴

Preliminary studies have found that injecting either the infant or the nursing mother with biotin may be an effective treatment for cradle cap.^{5 6} Studies of oral biotin have yielded mixed results in infants. Older preliminary studies and case reports suggest that 4 mg per day of oral biotin might be sufficient for mild cases of cradle cap, but 10 mg per day was required for more severe cases.⁷ Two more recent, controlled trials found that oral biotin (4 or 5 mg per day) produced no benefit.^{8 9} Thus, the scientific support for using oral biotin to treat cradle cap is weak. The role of biotin in adult seborrheic dermatitis has not been studied.

One physician reported that injections of B-complex vitamins were useful in the treatment of seborrheic dermatitis in infants.¹⁰ A preliminary trial found that 10 mg per day of folic acid was helpful in 17 of 20 cases of adult seborrheic dermatitis.¹¹ However, this study also found that oral folic acid did not benefit infants with cradle cap. A preliminary study found that topical application of vitamin B6 ointment (containing 10 mg B6 per gram of ointment) to affected areas improved adult seborrheic dermatitis.¹² However, oral vitamin B6 (up to 300 mg per day) was ineffective. Injections of vitamin B12 were reported to improve in 86% of adults with seborrheic dermatitis in a preliminary trial.¹³ Oral administration of vitamin B12 for seborrheic dermatitis has not been studied.