OBJECTIVES: Atopic dermatitis (AD) is one of the most prevalent dermatological conditions with autoimmune elements. Vitamin D has been found to modulate the immune system, and hence may be a beneficial adjunct therapy in the treatment of AD. This review aimed to identify literature assessing vitamin D supplementation and its effect on AD.

METHODS: Clinical study publications in AD from the last 15 years (January 1, 2008, onwards), involving low to moderate (400-2000 IU) vitamin D dose supplementation, were identified through targeted searches of the PubMed database, Google Scholar, and snowballing.

RESULTS: Nine clinical studies exploring the impact of vitamin D supplementation on AD outcomes were included. All enrolled children and/or adolescents, and two enrolled adults. Participant numbers ranged from 5 to 58. The majority of studies (78%) included participants with all severities of AD. All studies involved daily oral supplementation, with supplementation duration ranging from 1 to 3 months. Six studies (67%) assessed the use of vitamin D₃ (cholecalciferol) and only one study used vitamin D₂ (ergocalciferol). Daily supplementation dose ranged from 1000 to 2000 IU. The majority of studies (78%) allowed for continued use of other AD therapies. Clinical tools used to assess AD outcomes included the SCORing Atopic Dermatitis index (SCORAD; n=5) and the Eczema Area and Severity Index (EASI; n=3). All studies reported a reduction in SCORAD (range 21-74%, n=7) or EASI (29%, from n=1 of 2 reporting) score post-vitamin D supplementation, indicating improvement in clinical outcomes. No studies investigated patient-reported outcomes (PROs).

CONCLUSIONS: Evidence suggests that vitamin D can be a beneficial adjunct therapy in the treatment of AD. The use of vitamin D should, therefore, be considered when developing treatment strategies for AD. The absence of PROs in studies highlights a gap that should be addressed in future vitamin D supplementation research in AD.