fluids are unavailable or unsuitable for study [1&&].
Identification of tissue mast cells, for example, in
the laryngeal wall, by staining for immunohistochemical
markers such as CD117, has been proposed
for use in this setting [26].
Serum total tryptase measurements are not helpful
for confirmation of the diagnosis of anaphylaxis
at the time of the episode because the assay takes
several hours to perform; however, they can be
useful later, more so for confirmation of the clinical
diagnosis of venom or medication-induced anaphylaxis
than for confirmation of food-induced anaphylaxis
[1&&]. Serial monitoring of tryptase levels at the
time of presentation, 1–2h later, and at resolution is
reported to improve the sensitivity of the test [27].
MANAGEMENT OF ANAPHYLAXIS IN
HEALTHCARE SETTINGS
Appropriate preparation is the key to good patient
outcomes in anaphylaxis [1&&,28]. In a pediatric ED,
development and implementation of an anaphylaxis
protocol significantly improved the rate of
epinephrine administration, the rate of admission
to an observation unit, and the duration of observation
in this unit, and there were no significant
adverse effects from epinephrine [29&&]. In a retrospective
study [30] of pediatric ED patients with
food-related allergic reactions, factors that were
independently associated with a higher likelihood
of hospitalization included pre-ED epinephrine
treatment, and epinephrine treatment within 1 h
of triage.
Epinephrine is the preferred vasopressor for
treatment of anaphylactic shock [1&&,31]; however,
it is not always given promptly, even in hospitalized
patients. As an example, anaphylaxis can be difficult
to diagnose during anesthesia; consequently,
treatment with epinephrine can be delayed. In a
retrospective study [32], 45% of patients with anaphylaxis
during anesthesia developed shock, circulatory
instability, or cardiac arrest, yet only 83% of
these patients received epinephrine.
Even if epinephrine has not been given at all,
cardiovascular symptoms, including myocardial
infarction and arrhythmias, can occur during anaphylaxis
[1&&,33]. These complications also occur
after epinephrine overdose, regardless of route of
administration, but especially after an intravenous
bolus dose or overly rapid intravenous infusion
[34–36].
In a prospective randomized blinded study
[37] of young patients with acute cutaneous
allergic reactions during food challenges, in comparison
with diphenhydramine 1mg/kg, cetirizine
0.25mg/kg had a similar onset of action, similar