Relationship of vitamin D to pathogenesis and outcomes of hidradenitis suppurativa: a systematic review.

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by painful sinus tracts and significant scarring. Recent evidence suggests that vitamin D deficiency may play a role in the pathogenesis and outcomes of HS. This systematic review aims to evaluate the relationship between vitamin D levels and HS, exploring potential therapeutic benefits of vitamin D supplementation. This systematic review followed PRISMA guidelines and was registered with PROSPERO (ID:CRD42024566092). A comprehensive literature search was conducted in PubMed, Medline (OVID), and Web of Science using the keywords "hidradenitis suppurativa" and "vitamin D." Studies were screened for relevance, and non-randomized studies were assessed for quality using the MINORS score. Due to the heterogeneity of clinical outcome measures, a qualitative analysis was performed. A total of 77 records were identified, with 38 articles remaining after duplicates were removed. After full-text screening, 8 studies met the inclusion criteria. These studies, published between 2014 and 2024, included case-control, cross-sectional, and cohort studies. High prevalence rates of vitamin D deficiency (75-100%) were consistently observed among HS patients. Improved clinical outcomes with vitamin D supplementation were noted in several studies. There were significant correlations between vitamin D deficiency and higher clinical severity, and genetic alterations in vitamin D metabolism and keratinization pathways were identified in HS patients. This systematic review demonstrates a significant association between vitamin D deficiency and HS. Vitamin D's role in immune regulation and anti-inflammatory processes suggests its potential as a therapeutic agent for HS. However, further research is needed to determine optimal dosing and assess the protective effects of vitamin D supplementation in HS management.