Beneficial role for supplemental vitamin D₃ treatment in chronic urticaria: A randomized study

Background Observational reports have linked vitamin D with chronic urticaria, yet no randomized controlled trial has been conducted. Objective To determine whether high-dose vitamin D supplementation would decrease Urticaria Symptom Severity (USS) scores and medication burden in patients with chronic urticaria. Methods In a prospective, double-blinded, single-center study, 42 subjects with chronic urticaria were randomized to high (4,000 IU/d) or low (600 IU/d) vitamin D₃ supplementation for 12 weeks. All subjects were provided with a standardized triple-drug therapy (cetirizine, ranitidine, and montelukast) and a written action plan. Data on USS scores, medication use, blood for 25-hydroxyvitamin D, and safety measurements were collected. Results Triple-drug therapy decreased total USS scores by 33% in the first week. There was a further significant decrease (40%) in total USS scores in the high, but not low, vitamin D₃ treatment group by week 12. Compared with low treatment, the high treatment group demonstrated a trend (P =.052) toward lower total USS scores at week 12, which was driven by significant decreases in body distribution and number of days with hives. Beneficial trends for sleep quality and pruritus scores were observed with high vitamin D₃. Serum 25-hydroxyvitamin D levels increased with high vitamin D₃ supplementation, but there was no correlation between 25-hydroxyvitamin D levels and USS scores. There was no difference in allergy medication use between groups. No adverse events occurred. Conclusion Add-on therapy with high-dose vitamin D₃ (4,000 IU/d) could be considered a safe and potentially beneficial immunomodulator in patients with chronic urticaria. Trial Registration clinicaltrials.gov Identifier: NCT01371877.