Asthma, loss of consciousness, higher basal tryptase levels linked to biphasic anaphylaxis
Click Here to Manage Email Alerts
An asthma diagnosis, loss of consciousness and higher basal tryptase levels may be indicators of a biphasic anaphylactic reaction, according to a letter published in Clinical and Translational Allergy.
Based on these risk factors, providers should prolong their monitoring of these patients, Terence Langlois, medical intern in allergology at Université Paris-Saclay in Paris, and colleagues wrote.
According to the researchers, between 4% and 6% of patients with anaphylaxis experience a subsequent biphasic reaction without any elicitor re-exposure, and these reactions are more severe than monophasic anaphylaxis.
Close monitoring for up to 12 hours after an anaphylactic reaction is recommended. Identifying the patients who may be at risk for biphasic reactions, the researchers wrote, would improve their care.
The researchers retrospectively evaluated data of 237 adults referred for anaphylaxis from allergy to a tertiary-care university hospital between January 2017 and May 2020.
Of the 224 patients with monophasic reactions (mean age, 49.2 years; 87 men), 38 had asthma. Of the 13 patients with biphasic reactions (mean age, 49.8 years; five men), six had asthma. Among the patients with biphasic reactions, the mean delay between the first and second reaction was 8 hours (range, 1-48 hours).
The researchers found increased odds for a biphasic reaction with asthma (OR = 4; 95% CI, 1.05-14.81).
Also, all 13 patients (100%) with biphasic reactions lost consciousness during anaphylaxis, compared with 132 (58.9%) of those with monophasic reactions (P = .008).
Additionally, the patients with biphasic reactions had median basal tryptase levels of 6.1 µg/L, which was significantly higher than the 4.2 µg/L level observed among those with monophasic reactions (P = .009).
Among the patients with asthma, those with biphasic reactions had a median basal tryptase level of 5.3 µg/L whereas those with monophasic reactions had a level of 3.7 µg/L (P = .015), a difference that also reached significance.
The researchers noted that higher tryptase levels have been associated with severity of anaphylaxis and that their study is the first to suggest that basal tryptase levels are higher with biphasic than monophasic anaphylactic reactions.
Future studies could confirm whether higher basal tryptase is a risk factor for biphasic reactions and other severe outcomes of anaphylaxis, the researchers wrote, adding that the higher proportion of patients with asthma in the biphasic group could be an explanation.
Further, the researchers wrote, their study is the first to show a link between asthma comorbidity and biphasic anaphylaxis, with asthma known to increase anaphylaxis severity and severe asthma associated with elevated basal tryptase levels.
Perspective
Back to Top
This was an interesting article. My one concern is that only 13 patients actually had a biphasic reaction. With that said, it indicates a lower number (5.5%) than some prior studies. Also, the indication of asthma and tryptase as indicators is interesting. This needs to be replicated in studies with larger numbers and that are better stratified by trigger, such as food vs. venom. With that being said, this study builds upon the recent study from Casale and colleagues, giving us further direction regarding who should go to the emergency room after using epinephrine.
Reference:
Casale TB, et al. J Allergy Clin Immunol Pract. 2022;doi:10.1016/j.jaip.2022.04.040.
Collapse
Read more about
Click Here to Manage Email Alerts