Facts and speculations on vitamin d in prevention and treatment of atopic dermatitis.

Recently, age- and weight-specific recommendations for prevention, supplementation and treatment of vitamin D (VD) deficiency in the general population and in groups at increased risk of the deficiency (i.a. atopic dermatitis) has been presented by the Polish Experts group. VD regulates many physiological processes in the skin ranging from cellular proliferation, differentiation, and apoptosis to barrier maintenance and immune functions. VD deficiency has been associated with increased incidence and severity of atopic dermatitis. In addition, VD supplementation was shown to decrease atopic dermatitis severity in several studies, but the findings obtained in systematic reviews and meta-analyses are controversial.