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).