The Effects of Oral Vitamin D Supplement on Atopic Dermatitis: A Clinical Trial with Staphylococcus aureus Colonization Determination.

An increase in Staphylococcus aureus skin colonization in atopic dermatitis patients resulted from the reduction of cathelicidin production in these patients. Recently, an in vivo study demonstrated that vitamin D could stimulate cathelicidin production. Oral supplements of vitamin D might be beneficial in atopic dermatitis.To determine the effects of oral vitamin D supplements on clinical impact including Staphylococcus aureus skin colonization evaluation in atopic dermatitis patients.Twenty-four atopic dermatitis patients were included in this double-blind, placebo-controlled study. They were randomly assigned into 2 groups for oral 2,000 IUs/day of vitamin D, supplement and placebo. The lesional swab culture for S. aureus was done at week 0, 2 and 4. Clinical outcomes were assessed by SCORAD score, mexameter for erythema index and konometer for conductance were done at week 0, 2 and 4. Serum vitamin D levels were also determined at week 0 and 4.Twenty patients completed the protocol. S. aureus skin colonization, SCORAD score and erythema index were significantly reduced from baseline to week 4for vitamin D treated group comparing with placebo (p = 0.022, 0.028 and 0.014, respectively). There was an inverse correlation between serum vitamin D levels with S. aureus skin colonization and SCORAD score (r = -1.0, p < 0.001).Oral vitamin D supplement could reduce skin colonization of S. aureus and demonstrated the clinical improvement of patients with atopic dermatitis.