背景：在英国和美国，维生素B12（VitB12）缺乏症（VBD）影响约20％的60岁以上人群。如果未经治疗,它导致有害的健康结果。
目的：研究转诊到英国三个变态反应中心的VitB12超敏反应（VB12H）患者队列，并设计VB12H研究路径。
方法：2014年至2022年期间观察的29例患者接受了氰钴胺（CC）和羟基钴胺（HC）和IDT（0.1和0.01mg/ml）的SPT（1mg/ml）。皮肤试验阴性的患者使用指数或替代药物进行了VitB12药物激发试验（DPT）。
结果：29例患者中有18例（62％）出现VB12H。八个经历过的过敏反应（四个到HC，4至CC），并且对索引药物的皮肤测试呈阳性。一名患者对口服反应，七名患者对可注射VitB12反应。7名患者对一种形式的VitB12耐受DPT敏感，并选择了VitB12。一名立即患有VB12H的患者在口服钴胺素中与聚乙二醇反应。29例患者中有8例出现HSR延迟；4例患者耐受IM指数制剂，而2例患者耐受PO制剂。一名患者出现与SDRIFE一致的症状。三名患者因钴过敏而转诊。
结论：确认VB12H罕见。我们提出了一个全面的评估方案，其中包括VitB12皮肤测试，并考虑了VB12H患者的PEG过敏。
Vitamin B12 (Vit B12) deficiency affects approximately 20% of those above the age of 60 years in the United Kingdom and United States. If untreated, it leads to detrimental health outcomes.
To investigate a cohort of patients with Vit B12 hypersensitivity (VB12H) referred to 3 UK allergy centers and design a pathway for the investigation of VB12H.
A total of 29 patients seen between 2014 and 2022 underwent skin prick testing (1 mg/mL) with cyanocobalamin (CC) and hydroxycobalamin (HC) and intradermal testing (0.1 and 0.01 mg/mL). Patients with negative skin tests underwent a Vit B12 drug provocation test (DPT) with either the index or the alternative drug.
Of 29 patients, 18 (62%) presented with immediate VB12H. Eight experienced anaphylaxis (4 to HC and 4 to CC) and had positive skin tests to the index drug. One patient reacted to oral and 7 patients to injectable Vit B12. Seven patients sensitized to one form of Vit B12-tolerated DPT with an alternative Vit B12. One patient with immediate VB12H reacted to polyethylene glycol (PEG) in oral cobalamin. Of 29 patients, 8 presented with delayed hypersensitivity reaction; 4 patients tolerated the intramuscular index formulation, whereas 2 patients tolerated the per oral formulation. One patient presented with symptoms consistent with symmetrical drug-related intertriginous and flexural exanthema. Three patients were referred because of cobalt allergy.
Confirmed VB12H is rare. We propose a comprehensive evaluation protocol that includes Vit B12 skin tests and considers PEG allergy in patients presenting with VB12H.
