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.

Background Patients with severe asthma may present with characteristics representing overlapping phenotypes, making them eligible for more than one class of biologic. Our aim was to describe the profile of severe adult asthma patients eligible for both anti-IgE and anti-IL5/5R and to compare the effectiveness of both classes of treatment in real life. Methods This was a prospective cohort study that included adult severe asthma patients from 22 countries enrolled into the International Severe Asthma registry (ISAR) who were eligible for both anti-IgE and anti-IL5/5R. The effectiveness of anti-IgE and anti-IL5/5R was compared in a 1:1 matched cohort. Exacerbation rate was the primary effectiveness endpoint. Secondary endpoints included long-term-oral corticosteroid (LTOCS) use, asthma-related emergency room (ER) attendance and hospital admissions. Results In the matched analysis (n=350/group), the mean annualized exacerbation rate decreased by 47.1% in the anti-IL5/5R group and 38.7% in the anti-IgE group. Patients treated with anti-IL5/5R were less likely to experience a future exacerbation (adjusted IRR 0.76; 95% CI 0.64, 0.89; p<0.001) and experienced a greater reduction in mean LTOCS dose than those treated with anti-IgE (37.44% vs 20.55% reduction; p=0.023).) There was some evidence to suggest that patients treated with anti-IL5/5R experienced fewer asthma-related hospitalizations (IRR 0.64; 95% CI 0.38, 1.08), but not ER visits (IRR 0.94, 95% CI 0.61, 1.43). Conclusions In real life, both anti-IgE and anti-IL5/5R improve asthma outcomes in patients eligible for both biologic classes, however anti-IL5/5R was superior in terms of reducing asthma exacerbations and LTOCS use.