D2.247 - Vitamin D Status as a Modifiable Factor in Chronic Spontaneous Urticaria

Low vitamin D levels have been associated with several autoimmune diseases; however, evidence regarding the impact of vitamin D status on the course of chronic spontaneous urticaria (CSU) remains limited. This study aimed to evaluate the clinical efficacy of vitamin D supplementation in patients with CSU.

The study included 42 patients with CSU refractory to standard-dose antihistamine therapy and 15 healthy controls. Serum 25-hydroxyvitamin D (25(OH)D) levels, Urticaria Activity Score over 7 days (UAS7), and Urticaria Control Test (UCT) were assessed at baseline and after 4 weeks. All CSU patients received second-generation antihistamines at a fourfold dose and were divided into three groups: group A (25(OH)D >20 ng/ml; n=12), group B (25(OH)D <20 ng/ml; n=15), and group C (25(OH)D <20 ng/ml; n=15), who additionally received oral cholecalciferol 5000 IU/day for 4 weeks. Statistical analysis was performed using SPSS version 21. The study was approved by the local ethics committee.

Among the CSU patients, 28 (66.6%) were women and 14 (33.4%) were men. Baseline serum 25(OH)D levels were significantly lower in CSU patients compared with healthy controls (15.62±2.10 vs 31.58±6.4 ng/ml; p<0.001), with no significant difference between groups B and C at baseline (p=0.21). Baseline UAS7 scores were significantly lower and UCT scores significantly higher in group A compared with groups B and C. After 4 weeks of treatment, significant improvements in UAS7 and UCT were observed in groups A and C (p<0.05 for all), whereas no significant changes were detected in group B. A significant increase in serum 25(OH)D concentration was observed only in group C (p=0.018).

Low serum 25(OH)D levels in patients with CSU are associated with higher disease activity and poorer disease control. Vitamin D supplementation as an adjunct to high-dose antihistamine therapy significantly reduces urticaria activity and improves disease control in vitamin D–deficient patients.