Patients
This was a retrospective, observational and monocentric study. We examined the medical files of patients ≥ 15 years old who were referred to the allergology day hospital in one university hospital in Paris for exploring a suspected immediate hypersensitivity event between January 2017 and May 2020. We included patients with basal tryptase level measurement.
We extracted from the medical records the patient’s history and anaphylaxis characterization (1) and also severity of the reaction according to the Ring and Messmer classification (43), allergic status, medical antecedents and current treatments.
Patients with asthma were all diagnosed and followed up by a pulmonologist or a general practitioner.
All investigations such as basal tryptase measurement were performed at least 4 weeks after the hypersensitivity reaction. Plasma basal tryptase level was measured by the UniCAP-Tryptase fluoroimmunoassay method (Phadia, Thermo Fisher Scientific, Uppsala, Sweden) following the manufacturer’s instructions. Patients with basal tryptase level > 11 µg/L and/or REMA score ≥2 for Hymenoptera venom-elicited anaphylaxis (44) were suspected to have mast cell–related disorder and referred to hematology consultation for additional exploration. Allergy tests performed in the day hospital included skin tests (prick tests and intradermal tests), specific IgE measurements, and challenge tests for allergen reintroduction if necessary (drugs or foods).
We excluded patients if they had a diagnosis of mast cell disease or if their reaction did not meet the anaphylaxis criteria of the 2020 World Allergy Organization (1).