Decreased 25-hydroxyvitamin D levels in chronic spontaneous urticaria and its relationship with disease activity

Chronic spontaneous (idiopathic) urticaria (CSU) is a common skin disease that reduces the quality of life, and many factors can affect disease activity. This retrospective study evaluated the association between serum 25-hydroxyvitamin D levels and disease activity in patients with CSU compared to individuals without urticaria. The data of the patients was extracted from their medical records. CSU severity was assessed using the urticaria activity score, and serum vitamin D levels were measured by electrochemiluminescence. According to the urticaria activity score, CSU patients were divided into 3 groups; mild, moderate, and omalizumab-treated severe groups, and the vitamin D levels in these groups were compared. The mean (standard deviation) age and vitamin D level were 38.17 (12.67) years and 17.55 (9.27) ng/mL in the CSU group and 39.32 (11.99) years and 26.06 (9.62) ng/mL in the control group. The mean serum vitamin D level in CSU patients was significantly lower than that in the control group (P < .001). The mean vitamin D levels in the mild, moderate, and severe groups were 18.78 ± 9.78, 16.22 ± 9.23, and 17.65 ± 8.86, respectively. There was no statistically significant relationship between disease severity and vitamin D levels (P = .410). This study showed that patients with urticaria had reduced vitamin D levels compared with those in the control group. However, when we compared the subgroups of patients with CSU as mild, moderate, and severe, we did not find any difference.