Challenging dogmas: Intravenous versus oral beta-lactam antibiotic provocation tests.

Background: Drug provocation tests (DPT) are considered the gold standard procedure to ascertain the diagnosis of beta-lactam (BL) allergy. Regarding route of administration, current recommendations prioritize oral challenges, considering them safer, and reserving the intravenous route for drugs for which this is the only formulation. Objective: To compare in terms of tolerance and safety two protocols of BL DPT, using an oral protocol (OR-DPT) and an intravenous protocol (IV-DPT). Methods: A descriptive, retrospective study was performed, including adult patients who underwent IV-DPT or OR-DPT for suspected immediate or delayed hypersensitivity to BL antibiotics, over a period of 4 years (between January 2018 and December 2021). Demographical data, index hypersensivity reactions' characteristics and tolerance to DPT were reviewed. Results: A total of 1036 patients underwent DPT, mean age of 56.8 (standard deviation, SD, 17.8) years, 655 were women (63.2%). Immediate drug hypersensitivity reactions (DHR) had occurred in 564 of patients (54.4%). OR-DPT were performed in 439 (42.4%) and IV-DPT in 597 (57.6%). The frequency of reactions during DPT, regardless of the route used, was low (3.6%): only 16 (3.6%) in OR-DPT and 21 (3.5%) in IV-DPT. From IV-DPT, 16 out 21 DHR during DPT were immediate compared with 4 out of 16 in OR-DPT. Adjusted relative risk of developing a hypersensitivity reaction during IV-DPT versus OR-DPT was 1.13 (95% confidence interval (CI)0.57-2.22). Conclusion: The results suggest that OR-DPT and IV-DPT are both safe procedures when adequately performed. However, IV-DPT protocols showed a higher rate of immediate DHR during DPT probably due to the selection of basal high-risk patients to undergo IV-DPT. In conclusion, IV-DPT may be considered as an option for challenges in drug-allergy studies, entailing a precise administration.

One-Dilution Rapid Desensitization Protocol to Chemotherapeutic and Biological Agents: A Five-Year Experience.

BACKGROUND: Rapid drug desensitization (RDD) becomes a crucial procedure to allow treatment continuation in patients who suffer drug hypersensitivity reactions (DHRs) to chemotherapeutic (CMT) and biological agents (BA). OBJECTIVE: The aim of the study was to compare the efficacy and safety of a one-bag dilution protocol (1DP) with a conventional three-bag dilution protocol (3DP) for desensitization of patients with CMT or BA hypersensitivity. METHODS: Retrospective analysis of patients with immediate DHRs to CMT or BA who underwent at least 1 RDD procedure in our department between 2014 and 2019 was performed. Demographical data, clinical history, skin tests, tryptase levels, and risk assessment were registered. The safety, tolerability, occurrence, and severity of breakthrough reactions (BTR) with 3DP and 1DP were compared. RESULTS: After the allergy workup, 157 patients fulfilled criteria to undergo RDD (137 females, mean age: 60.44 ± 12.6 years). A total of 639 RDDs (543 CMT and 96 BA) were performed using 3DP in 205 (48 patients) and 1DP in 434 (109 patients). Almost all procedures (636) were completed successfully. No BTR occurred in the first RDD in 52% and 51% of the 3DP and 1DP, respectively. Most BTR were mild. Moderate-severe BTR occurred in 17% with 3DP and 9% with 1DP. There were no statistical differences between protocols regarding the rate and severity of BTR. CONCLUSIONS: RDD with 1DP to CMT and BA has equivalent outcomes to a 3DP desensitization in a selected population of patients in terms of efficacy, tolerability, and safety. Moreover, 1DP reduces the time required for RDD and simplifies the logistics.

IgE-Related Chronic Diseases and Anti-IgE-Based Treatments.

IgE is an immunoglobulin that plays a central role in acute allergic reactions and chronic inflammatory allergic diseases. The development of a drug able to neutralize this antibody represents a breakthrough in the treatment of inflammatory pathologies with a probable allergic basis. This review focuses on IgE-related chronic diseases, such as allergic asthma and chronic urticaria (CU), and on the role of the anti-IgE monoclonal antibody, omalizumab, in their treatment. We also assess the off-label use of omalizumab for other pathologies associated with IgE and report the latest findings concerning this drug and other new related drugs. To date, omalizumab has only been approved for severe allergic asthma and unresponsive chronic urticaria treatments. In allergic asthma, omalizumab has demonstrated its efficacy in reducing the dose of inhaled corticosteroids required by patients, decreasing the number of asthma exacerbations, and limiting the effect on airway remodeling. In CU, omalizumab treatment rapidly improves symptoms and in some cases achieves complete disease remission. In systemic mastocytosis, omalizumab also improves symptoms and its prophylactic use to prevent anaphylactic reactions has also been discussed. In other pathologies such as atopic dermatitis, food allergy, allergic rhinitis, nasal polyposis, and keratoconjunctivitis, omalizumab significantly improves clinical manifestations. Omalizumab acts in two ways: by sequestering free IgE and by accelerating the dissociation of the IgE-Fcε receptor I complex.