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Vitamin B12 desensitization and provocation: Ten-year clinical experience.
Fatma Dindar Çelik1, Kurtuluş Aksu1, Özge Göktürk1
1University of Health Sciences, Ankara Ataturk Sanatorium Training and Research Hospital, Department of Immunology and Allergy, Ankara, Türkiye.
The World Allergy Organization Journal
|June 8, 2026
Summary
Vitamin B12 hypersensitivity reactions (HSRs) are rare but manageable. Drug provocation tests (DPT) and desensitization protocols allow safe vitamin B12 administration in patients with HSRs or allergies.
Area of Science:
- Allergy and Immunology
- Pharmacology
- Nutritional Science
Background:
- Vitamin B12 is an essential nutrient, yet hypersensitivity reactions (HSRs) are infrequently reported.
- Understanding HSRs to vitamin B12 is crucial for patient management and treatment adherence.
Purpose of the Study:
- To characterize HSRs associated with vitamin B12 preparations.
- To evaluate the efficacy of desensitization and drug provocation tests (DPT) in managing vitamin B12 hypersensitivity.
Main Methods:
- Retrospective descriptive study of patients with vitamin B12 deficiency and HSRs or allergy concerns.
- Drug provocation tests (DPT) for low-risk patients; desensitization protocols for high-risk patients.
- Assessment of successful completion based on the absence of immediate or delayed reactions during protocols.
Main Results:
- Of 44 patients, 28 had prior HSRs to cyanocobalamin; 16 were hesitant due to other drug allergies.
- DPT performed in 86.4% and desensitization in 13.6% of patients.
- Low incidence of immediate-type HSR (2.5% during DPT) and desensitization (12.5% during desensitization). All skin tests were negative.
Conclusions:
- DPT is a reliable method for assessing low-risk patients, preventing unnecessary restrictions.
- Desensitization protocols facilitate continued vitamin B12 treatment in high-risk individuals.
- These procedures ensure safe and effective vitamin B12 therapy management.
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