Biotin is a water-soluble B-complex vitamin. It was discovered by Bateman in 1916. It is composed of a tetrahydroimidizalone ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring. It is a coenzyme in the metabolism of fatty acids and leucine, and it plays a role in gluconeogenesis. Patients with palmoplantar pustulosis had metabolic derangements of glucose and fatty acids as well as immune dysfunction derived from biotin deficiency, which led to abnormal manifestations of skin, bone and other tissues and organs. All of the clinical, metabolic and immune disorders were improved by biotin administration. Diabetics may also benefit from biotin supplementation. The scaly skin changes that occur in people with phenylketonuria may be related to poor ability to use biotin. Increasing dietary biotin has been known to improve seborrheic dermatitis in these cases.
