Background: Chemotherapy (CHT) and monoclonal antibodies (mAbs) have been described as frequent causes of drug allergy. Currently, rapid drug desensitization (RDD) is a widely recognized and safe procedure extensively used to manage patients with drug hypersensitivity reactions (DHR). Nevertheless, despite its effectiveness, RDD can occasionally be hampered by severe breakthrough reactions (BTR) during the procedure, potentially leading to its failure.   Objective: Evaluate the usefulness and safety of adrenaline infusion (AI) as a coadjuvant during RDD in patients with severe DHR during standard desensitization protocols.      Methods: Retrospective observational study, analyzing data from patients who underwent RDD to CHT or mAbs in a tertiary hospital from January-2015 to January-2024. We included patients who required the use of AI to safely achieve RDD after a severe initial DHR or failure of standard RDD protocol due to repeated DHR. Comorbidities, adrenaline doses and adverse events (AE) were assessed.    Results: Forty-two patients met the inclusion criteria. Seventy-seven percent ( n=32) were women with a mean age of 57 years(range 32-83). Most frequent drugs involved in DHR were platinum-salts 58%, mAbs 26% and taxanes 14%. A total of 151 RDD were performed with coadjuvant AI. Skin tests were positive in 69% of patients. The most frequent initial BTR (65%, n=28) was moderate or severe anaphylaxis. The most common adverse events (AE) associated with AI were trembling and tachycardia (14% and 7% respectively). These symptoms subsided after reducing the AI infusion rate. The median cumulative dose of adrenaline administrated during the entire RDD procedure was 0.76µg(IQR 0.4-1.2µg SD 3.05), with a median infusion rate of 8ml/h(IQR 4-15ml/h), and median AI maximum rate of 3.33µg/min(IQR 2-5.3µg/min).       Conclusions: AI is a useful and safe therapeutic tool for selected high-risk desensitization procedures, contributing to mitigate severe DHR with mostly minor AE.

Background: The occurrence of prodromes has been associated with swelling in hereditary angioedema (HAE). The aim of the study was to analyse the frequency of prodromal signs, the level of awareness among HAE patients and to understand the actions taken by patients when they experienced them. Methods: An online survey to assess patient experiences of prodromal symptoms was conducted among 208 HAE patients from the UK and Spain. Results: 60% of HAE patients who experience prodromes can always or usually predict an impending swelling. Almost 40% of participants noticed prodromes within the 2 hours preceding an HAE attack. Tiredness/fatigue (64%), pressure or tightness in the skin (53%) and abdominal pressure (52%) were the most reported early symptoms. C1-esterase inhibitor (C1-INH) and icatibant were prescribed to 75% and 65% of participants, respectively. 56% of participants in the UK reported self-medicating at the time of prodrome, whereas 65% of patients in Spain preferred to wait or relax when early symptoms began. 30% of patients said they usually took their medication within 1 hour of experiencing the prodrome. The percentage of patients who needed only one injection to treat the attack increased when patients took their medication early in the prodrome (from 55 to 66%). Conclusions: The majority of patients who have early symptoms were usually or always able to predict that a swelling would occur. Early treatment of HAE attacks is associated with less medication usage, but there is still no common understanding of what ‘early treatment’ means.