Purpose of review To review the key nutritional factors associated with hair loss in long-term parenteral nutrition patients.

Recent findings The phenomenon of unexplained hair loss is multifactorial, and nonstandard definitions are applied. Deficiencies of essential fatty acids resulting in alopecia and other symptoms appear to have been eliminated by regular use of lipid-containing parenteral nutrition. Zinc is the most frequently suspected deficiency with rapid clinical responses reported from zinc therapy. Alopecia in some infants on parenteral nutrition has been relieved in a few weeks by selenium supplementation as selenite. There may be a relationship between iron depletion and diffuse hair loss in home parenteral nutrition patients at higher risk of anaemia. A serum ferritin level of 70 μg/l should be targeted when hair loss is unexplained. However, there is limited data correlating cessation of hair loss with iron therapy and insufficient evidence to recommend iron supplementation in patients without anaemia. Parenteral nutrition-associated biotin deficiency has not been reported since the vitamin has been routinely added to parenteral nutrition. However, marginal biotin status, associated with diffuse hair loss, could still be prevalent.

Summary Micronutrient status is infrequently monitored and current recommendations for supplementation are nonspecific for hair loss in long-term parenteral nutrition. Studies are required to determine the incidence of marginal zinc, selenium, iron or biotin deficiencies that could manifest as hair loss.