News, Views, & Reviews

As the prevalence of atopic dermatitis increases, so does interest in “natural” treatment options as well as prescription medications to address this chronic disease. While case studies support the use of dietary supplements to treat atopic dermatitis, only recently have clinical trials been published to formally evaluate their efficacy. The most commonly used dietary supplements for atopic dermatitis are vitamin D, zinc, and essential fatty acids. Other supplements such as vitamin E, selenium, probiotics, and several oils such as hempseed, buckthorn, and evening primrose, have less evidence to support their use. For patients interested in a supplement-based treatment plan, dermatologists have several evidence-based interventions to recommend.

Patients may ask their dermatologist for recommendations on supplements as a complement or as an alternative to prescription medications. Dermatology patients may be concurrently treated by a naturopath who may prescribe oral or topical supplements for atopic dermatitis. Regardless of a physician's position on supplement use, being able to intelligently discuss supplement use with our patients enhances our effectiveness and the safety of our patients. When recommending supplementation, physicians should be aware of potential medication interactions, possible adverse events, and the potential for overdose.

A new Cochrane review published this year¹ highlights the limited evidence to date for use of these supplements. Among them, the Cochrane group found evidence that only essential fatty acids (EFAs) modestly improve atopic dermatitis. Their meta-analysis was limited by strict criteria for inclusion; just 11 studies following only 596 patients in total. Smaller studies excluded from the meta-analysis do suggest a benefit from each of these three supplements.

As the many effects of vitamin D become better appreciated, the use of both oral and topical vitamin D for treatment of skin disease is being revisited. Small studies suggest that oral vitamin D supplementation, particularly in northern climates where vitamin D deficiency is common, may help atopic dermatitis. Ultraviolet B (UVB) light is effective in treating atopic dermatitis, and it may be mediated in part by activating the production of vitamin D₃ in the skin. Topical vitamin D in the form of calcipotriene (Dovonex) and calcitriol (Vectical) are used for psoriasis and have been considered for treatment of atopic dermatitis. To date, topical vitamin D preparations have been too irritating to be effective for atopic skin and can exacerbate skin disease.

Low vitamin D levels correlate with increased severity of atopic dermatitis in children,² suggesting that vitamin D supplementation may improve the symptoms of atopic dermatitis. An Italian group evaluated 37 children at a single center with atopic dermatitis. Each was evaluated for atopic dermatitis via the SCORAD index and measured for serum levels of vitamin D₃ and specific immunoglobulin E (IgE) to Staphylococcus aureus and to Malassezia furfur. Among these children, severity of atopic dermatitis was associated with lower vitamin D level (P<.05) and increased titers of IgE to both S aureus and M furfur. Causality of these associations, or their response to vitamin D supplementation, was not evaluated among this group.

Further studies show that oral vitamin D supplementation could be a treatment option for atopic dermatitis. One rigorous double- blind, randomized, placebo-controlled trial³ of 60 individuals older than 14 years with atopic dermatitis compared supplementation with 1,600 IU of cholecalciferol (vitamin D₃) with placebo capsules over a 60-day period. These patients ranged from mild to severe disease; severity was assessed by the standardized SCORAD score at the initiation and conclusion of the trial. At the conclusion of the study, patients with vitamin D supplementation showed clinical improvement scored by a blinded clinician, while those using placebo did not. Improvement was seen in mild, moderate, and severe atopic dermatitis. Adverse effects were not reported; the dropout rate was up to 20% in the placebo group (6 of 30 patients) for unclear reasons.

A second randomized, double-blind, placebo-controlled trial⁴ evaluated oral vitamin D supplementation on atopic dermatitis severity. Forty-five adults with atopic dermatitis were randomized to be treated with 1,600 U vitamin D₃ or placebo for a 60-day period. Patients were evaluated with the clinical SCORAD instrument and serum level of vitamin D before and after the study period. Patients treated with oral vitamin D for two months showed, on average, a 35% improvement in their atopic dermatitis. Vitamin D levels improvement in treated patients; however, serum vitamin D levels did not correspond to degree of clinical improvement.

Narrow-band UVB (NB-UVB) has long been used to treat atopic dermatitis. Its mechanism of action is postulated to be via anti-inflammatory effects and direct anti-itch effects. Narrow-band UVB also increases skin and serum levels of vitamin D₃. A group in Finland⁵ measured how clinical response to NB-UVB