Introduction and objective Drugs are a frequent cause of severe anaphylactic reactions. Clinical epidemiology of drug-induced anaphylaxis (DIA) supports the identification of the most frequent eliciting drug groups, risk factors, symptoms and treatment procedures. Our aim was to analyze data to promote better recognition and long-term management of affected individuals. Methods Data from the European Anaphylaxis Registry (2007-2019) with 1,815 cases of drug-induced anaphylaxis were analyzed regarding demographics, elicitors, symptoms, comorbidities, and treatment. Results The most frequent eliciting groups of drugs were analgesics (41.27%) – with non-steroidal anti-inflammatory drugs (NSAIDs) being the most common subgroup (65.42%) – antibiotics (33.17%), local anesthetics (7.38%) and radiocontrast media (5.18%). Adrenaline was used more often in patients with DIA (23.20%) than in anaphylaxis due to other causes (17.82%). The majority of events occurred in female patients (65.34%), although they were admitted to hospital (29.01%) or an intensive care unit (ICU) (9.61%) less often. Skin symptoms were most common (84.02%), while gastrointestinal symptoms were reported less frequently (30.25%). Compared to other anaphylactic reactions in the registry (food/insects) severe reactions occurred significantly more often in DIA (5.62% vs. 1.67%). Hospitalization (31.63%) and ICU admission rates (11.85%) were significantly higher in DIA than anaphylactic reactions to other elicitors (27.58% and 5.45%). Conclusions DIA affects middle aged females more frequently and is more severe in elderly males in the sample observed. Analgesics and antibiotics are the leading causes of DIA. Adrenaline was rarely administered to patients, even though it is recommended by guidelines.

Systemic allergic reactions to vaccines are very rare. In this study we assessed the management and outcome suspected SARS-CoV-2 vaccine hypersensitivity. We present data of 219 individuals, who experienced symptoms suspicious for an allergic reaction after the first (n=214) or the second vaccination (n=5). 195 reactions occurred after the first application of mRNA-based vaccines (157 Comirnaty®, and 38 Spikevax®) and eighteen reactions were reported after first application of a vector vaccine (Vaxzevria®). Of these 162 experienced immediate symptoms. Skin symptoms occurred in 91 cases. The most frequent cutaneous symptom was angioedema (n=45), followed by generalized urticaria (n=36) and generalized erythema/flush (n=20). 70 patients had cardiovascular symptoms, 45 showed respiratory symptoms and gastrointestinal symptoms were recorded in 14 patients. The allergological assessment of 334 individuals (219 with reactions after COVID vaccination and 115 with a history of vaccine related reactions) showed in 17% a suspicion of sensitization against the SARS-CoV-2 vaccine and/or their ingredients defined as one positive skin test and/or BAT. The majority of the SPT/IDT with the vaccines were negative. Of the 214 patients with suspected allergic symptoms after the first vaccination, 67/67 patients tolerated the re-vaccination. In this study, 334 individuals of a cohort resembling >2000 persons presenting for an allergy workup regarding SARS-CoV-2 vaccination only 45 were diagnosed in concordance with the anaphylaxis definition of the Brighton collaboration with anaphylactic immediate hypersensitivity reaction after SARS-CoV-2 vaccination. Identifiable characteristics of these patients with suspected, but also diagnosed SARS-CoV-2 vaccine hypersensitivity were female gender and the symptom angioedema. Overall, IgE-mediated hypersensitivity towards SARS-CoV-2 vaccines is extremely low and not increased in comparison to the reported hypersensitivity for other vaccines.