Biotin deficiency (Q39925)

Isolated biotin deficiency is rare. Signs of biotin deficiency in humans have been demonstrated in individuals who consume raw egg white over long periods and in total parenteral nutrition (TPN) before biotin supplementation in patients with malabsorption. The clinical findings of biotin deficiency include dermatitis, conjunctivitis, alopecia, and central nervous system abnormalities. In adults fed raw egg white (which contains avidin, a protein that binds biotin with such high affinity that it renders it biounavailable) or receiving biotin-free TPN for months to years, thinning of hair, frequently with loss of hair colour, has been reported. Most adults with the deficiency demonstrate a red, scaly, skin rash, frequently around the eyes, nose, and mouth. Most of the adults have neurological symptoms, including depression, lethargy, hallucinations, and paraesthesia of the extremities.