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

Background: 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.

Objective: To determine the effects of oral vitamin D supplements on clinical impact including Staphylococcus aureus skin colonization evaluation in atopic dermatitis patients.

Material And Method: 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.

Results: 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).

Conclusion: Oral vitamin D supplement could reduce skin colonization of S. aureus and demonstrated the clinical improvement of patients with atopic dermatitis.