Higher basal tryptase, asthma and loss of consciousness in anaphylaxis
are associated with biphasic reactions
Abstract
Background: Anaphylaxis is the more severe form of immediate
hypersensitivity. It can be life-threatening and therefore requires fast
and appropriate medical management. After a first hypersensitivity
phase, a recurrence of symptoms without an elicitor re-exposure may
occur, called a biphasic reaction. The aim of this study was to identify
biological and clinical predictors of biphasic reactions in patients
with anaphylaxis. Methods: We retrospectively compared patients
with monophasic anaphylaxis to those with biphasic anaphylaxis from an
allergology day hospital in a French university hospital between January
2017 and May 2020. Results: Among the 237 patients, the rate of
biphasic reactions was 5.5% (n = 13). The odds of a biphasic reaction
was increased with asthma (p = 0.021; odds ratio = 4 [95% confidence
interval 1.05-14.81]) and loss of consciousness during anaphylaxis (p
= 0.008) as compared with monophasic anaphylaxis. Basal tryptase levels
were significantly higher with biphasic than monophasic anaphylaxis (p =
0.009). Conclusions: Asthma and unconsciousness during the
first phase of anaphylaxis could be associated with a biphasic reaction
. Elevated basal tryptase was linked to biphasic reactions,
which should be further explored.