Description of biphasic patients
During the study period, 237 patients with available tryptase
measurements and a suspected anaphylaxis event consulted at our allergy
center (Figure 1); 13 (5.5%) had a biphasic reaction. Detailed
characteristics of these patients are in Table 1.
Six of the 13 patients (46%) presented a severe secondary reaction
(Ring and Messmer grade III-IV), whereas 7 patients (64%) had a mild or
moderate reaction (Ring and Messmer grade I-II). The mean delay between
the first and second reaction was 8 hr (range 1-48). As compared with
the first reaction, the second was less severe for 5 (38.5%) patients,
as severe for 7 (53.8%) patients and more severe for only one (7.7%)
patient. Nine patients required a transfer to an intensive care unit for
the biphasic reaction, and 2 were already hospitalized when the biphasic
reaction occurred. The identified allergens were Hymenoptera venom for 6
patients, neuro-muscular blocking agents (NMBAs) for 4 patients,
antibiotics for 2 patients, and seafood for one patient.