Desensitization to colecalciferol in 18 patients with immediate hypersensitivity reactions.

Introduction: Hypersensitivity reactions (HSRs) to colecalciferol (vitamin D) have been rarely reported and the mechanism is unknown. As an alternative treatment was not recommended for vitamin D deficiency, a desensitization protocol with colecalciferol can be performed. We found that there is no standard desensitization protocol for vitamin D. In this study, we aimed to investigate clinical features and skin test results of patients with HSRs to the vitamin D and effectiveness of the 6-step desensitization protocol in which we applied oral drops of colecalciferol.

Method: This retrospective cross-sectional study included 18 patients with a history of HSRs to oral vitamin D supplements and patients who were planned to receive oral vitamin D replacement. Before desensitization, some of the patients underwent skin tests (skin prick test and intradermal test) with colecalciferol, and the results were recorded. Skin tests were not performed in patients with a history of drug use (antihistamine, systemic steroid, omalizumab, etc.) that affected the results of skin tests. All patients were applied an one bag 6-step desensitization protocol with colecalciferol. Vitamin D3 solution was administered totally 30 drop (4000 IU)/day (1 drop:133.33 IU of 3333 IU/mL) dose of colecalciferol (Devit-3®, DEVA-Türkiye, 15 mL/50,000 IU, 1 mL = 25 drop) at 15-minutes intervals without premedication.

Results: The patient group consisted of 16 female subjects (89%); the mean age was 46 ± 12 years. When the patients were evaluated in terms of the risk of hypersensitivity reactions according to their clinical history, 5 patients had a history of anaphylaxis with vitamin D preparations (colecalciferol oral drop, n = 3; colecalciferol capsule, n = 2), and 13 patients had a history of HSRs other than anaphylaxis with isolated cutaneous reactions (pruritus, flushing, urticaria and angioedema) (n = 11, colecalciferol oral drop; n = 2, colecalciferol capsule). Skin prick test (SPT) and intradermal test (IDT) were performed on 9 patients. SPTs and IDTs were negative in all patients. Urticaria occur during desensitization in only one patient but vitamin D replacement was performed within the following 48-72 h after HSRs. All other patients tolerated 30 drop (4000 IU) and have continued to take same dose every day for the last 6 weeks with no adverse reactions.

Conclusion: Desensitization with oral vitamin D preparations has a crucial role for patients who can not receive vitamin D supplements by other ways. Vitamin D drop forms, which are better absorbed than capsule forms which contains the lowest units per/mL without the need to dilute the preparation, not contain any additives with HSRs potential such as gelatin and peanut oil are good option. Our 6-step desensitization protocol with oral drop of colecalciferol is a reliable protocol in patients with a history of vitamin D HSRs.