Severe vitamin D deficiency increases the risk of severe cutaneous adverse reactions.

Vitamin D deficiency has been reported to be associated with allergic diseases and dermatological disorders. We investigated the role of vitamin D in drug-induced non-immediate hypersensitivity reactions by measuring serum vitamin D levels in 60 patients diagnosed with non-immediate drug hypersensitivity reactions and in 60 patients who tolerated the same medication without any allergic reactions. The results showed that serum vitamin D levels were significantly lower in patients with severe cutaneous adverse reactions (SCARs) (13.56 ± 6.23 ng/mL) compared to patients with mild reactions (17.50 ± 7.49 ng/mL) and the drug-tolerant control group (17.42 ± 7.28 ng/mL), with p values of 0.031 and 0.015, respectively. The proportion of severe vitamin D deficiency (< 10 ng/mL) was much higher in SCAR patients compared to drug-tolerant subjects (36.7% vs. 11.7%, p value = 0.005). After adjusting for age, gender, region of residence, and concurrent illnesses, patients with severe vitamin D deficiency had significantly increased in-hospital mortality (odds ratio 16.04; 95% CI, 1.25-206.12, p value = 0.03). In conclusion, the risk of developing SCARs and in-hospital mortality was increased in patients with severe vitamin D deficiency. Further investigations should be conducted to elucidate the role of vitamin D in the development of SCARs.