RESUMO
BACKGROUND: 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. OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.
Assuntos
Anafilaxia , Hipersensibilidade a Drogas , Humanos , Pessoa de Meia-Idade , Anafilaxia/tratamento farmacológico , Hipersensibilidade a Drogas/etiologia , Testes Intradérmicos , Polietilenoglicóis , Testes Cutâneos/efeitos adversos , Vitamina B 12/uso terapêutico , Vitaminas , Estudos RetrospectivosRESUMO
Orthostatic intolerance and other autonomic dysfunction syndromes are emerging as distinct symptom clusters in Long Covid. Often accompanying these are common, multi-system constitutional features such as fatigue, malaise and skin rashes which can signify generalized immune dysregulation. At the same time, multiple autoantibodies are identified in both Covid-related autonomic disorders and non-Covid autonomic disorders, implying a possible underlying autoimmune pathology. The lack of specificity of these findings precludes direct interpretations of cause and association, but their prevalence with its supporting evidence is compelling.