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Background: Mastocytosis and monoclonal mast cell (MC) activation syndrome (MMAS) are heterogeneous conditions characterized by the accumulation of atypical MCs. Despite the recurrent involvement of KIT mutations, the pathophysiologic origin of mastocytosis and MMAS is unclear. Although hereditary α-tryptasemia (HαT, related to TPSAB1 gene duplication) is abnormally frequent in these diseases, it is not known whether the association is coincidental or causal., Objective: We evaluated the prevalence of HαT in all mastocytosis subtypes and MMAS and assessed the pathophysiologic association with HαT., Methods: Clinical data, laboratory data, KIT mutations, TPSAB1 duplication (assessed by droplet digital PCR), and HαT prevalence were retrospectively recorded for all patients with mastocytosis and MMAS registered in the French national referral center database and compared to a control cohort. To increase the power of our analysis for advanced systemic mastocytosis (advSM), we pooled our cohort with literature cases., Results: We included 583 patients (27 with MMAS and 556 with mastocytosis). The prevalence of HαT in mastocytosis was 12.6%, significantly higher than in the general population (5.7%, P = .002) and lower than in MMAS (33.3%, P = .02). HαT + patients were more likely to have anaphylactic reactions and less likely to have cutaneous lesions than HαT - patients (43.0% vs 24.4%, P = .006; 57.7% vs 75.6%, respectively, P = .006). In the pooled analysis, the prevalence of HαT was higher in advSM (11.5%) than in control cohorts (5.2%, P = .01)., Conclusion: Here we confirm the increase incidence of anaphylaxis in HαT + mastocytosis patients. The increased prevalence of HαT in all subtypes of systemic mastocytosis (including advSM) is suggestive of pathophysiologic involvement., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Anaphylaxis, which is rare, has been reported after COVID-19 vaccination, but its management is not standardized., Method: Members of the European Network for Drug Allergy and the European Academy of Allergy and Clinical Immunology interested in drug allergy participated in an online questionnaire on pre-vaccination screening and management of allergic reactions to COVID-19 vaccines, and literature was analysed., Results: No death due to anaphylaxis to COVID-19 vaccines has been confirmed in scientific literature. Potential allergens, polyethylene glycol (PEG), polysorbate and tromethamine are excipients. The authors propose allergy evaluation of persons with the following histories: 1-anaphylaxis to injectable drug or vaccine containing PEG or derivatives; 2-anaphylaxis to oral/topical PEG containing products; 3-recurrent anaphylaxis of unknown cause; 4-suspected or confirmed allergy to any mRNA vaccine; and 5-confirmed allergy to PEG or derivatives. We recommend a prick-to-prick skin test with the left-over solution in the suspected vaccine vial to avoid waste. Prick test panel should include PEG 4000 or 3500, PEG 2000 and polysorbate 80. The value of in vitro test is arguable., Conclusions: These recommendations will lead to a better knowledge of the management and mechanisms involved in anaphylaxis to COVID-19 vaccines and enable more people with history of allergy to be vaccinated., (© 2022 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Chronic spontaneous urticaria (CSU) is characterized by recurring hives and/or angioedema lasting for at least 6 weeks, while Chronic Inducible Urticaria (CIndU) is triggered by specific stimuli. A recent Turkish study analyzed 423 patients with different types of CIndU and found that isolated CIndU was more common than cases where CSU coexisted with CIndU. The study also identified demographic differences among CIndU subtypes, with cholinergic urticaria affecting younger male patients more frequently. Systemic reactions were observed in some subtypes of CIndU, such as cold urticaria and cholinergic urticaria, but not in CSU. Understanding the distinct clinical presentations of CIndU subtypes is important for developing appropriate therapeutic approaches. [Extracted from the article]

(C) Positive prick test with undiluted Desomedine on delayed reading at day 2 (same prick test as in B) gl Prick tests were performed with undiluted Desomedine (hexamidine 0.1%), and these confirmed both immediate and delayed type hypersensitivity on immediate (Figure 1B) and delayed readings on day (D)2 (Figure 1C). Although allergic contact dermatitis in response to antiseptics is common, we should be aware that occasionally this may co-exist with immediate-type hypersensitivity, and also with molecules frequently sold over the counter. Keywords: case report; delayed hypersensitivity; hexamidine; immediate hypersensitivity EN case report delayed hypersensitivity hexamidine immediate hypersensitivity 580 582 3 10/22/21 20211101 NES 211101 CASE REPORT A 66-year-old man with a history of arterial hypertension (treated by dietary approaches only), allergic rhinitis, asthma, and atopic dermatitis, developed a grade II anaphylactic reaction 5 minutes after the first intranasal application of hexamidine (Desomedine, Chauvin Bausch & Lomb laboratory, Montpellier, France) for a cold. [Extracted from the article]