Nut allergies caused by alcohol

Flavorings present in certain alcohols could cause severe allergic reactions, according to a new study from McGill University. Researchers also note that adults who know they are allergic do not use epinephrine enough before going to the emergency room.

“It was known that alcohol consumption increases the severity of allergic reactions,” explains Roy Khalaf, lead author and medical student at the Faculty of Medicine at McGill University, who is one of the co-authors of the published study. in the International Archives of Allergy and Immunology. “We found that alcohol is more commonly associated with nut allergies. Our hypothesis to explain this new observation is that certain alcohols have nutty aromas. »

Mr. Khalaf cites, for example, amaretto, galliano or amadeus. Even artificial flavors could be to blame.

The study analyzed the files of 1,135 adults who presented with an allergic reaction to the MUHC emergency room between 2011 and 2023. Half of the cases concerned nut allergies. In this group, one in six patients had consumed alcohol before the allergic reaction.

Other studies have shown that alcohol increases the risk of a serious allergic reaction because it causes vasodilation, the increase in the diameter of blood vessels, according to Khalaf. “Vasodilation accentuates anaphylactic shock”, the cessation of breathing often associated with serious allergic reactions.

Other hypotheses exist to explain the fact that alcohol increases the severity of allergic reactions, notes the study.

But alcohol is more present in patients with allergic reactions to nuts, compared to those who arrive at the emergency room because of an allergic reaction to other foods, such as milk or fish, or to a bite from a nut. insect or medication. This is what led McGill researchers to postulate an allergic effect of nut flavors in certain alcohols.

A different reaction depending on age?

The study aimed to determine if the symptoms of adults who arrive at the emergency room because of an allergic reaction are different from children. This is not the case.

Two other analyzes were carried out in this sample of 1135 adults. One – seeing what type of alcohol was associated with allergic reactions to nuts – didn’t work because patients didn’t report that information. The other, on different symptoms in the elderly compared to adults under 65, will be published in the coming months.

“We want to help emergency physicians recognize serious allergic reactions more quickly,” says Mr. Khalaf.

Epinephrine

The other clinical impact of the study which has just been published will be on patients. “We see a lot of people who have already had an anaphylactic reaction, and therefore who normally have a prescription for epinephrine, who arrive at the emergency room without having received any,” says Mr. Khalaf. However, the severity of allergic reactions is less if you receive epinephrine quickly. »

Epinephrine is a medication to counter an allergic reaction that is given by injector that is relatively easy to use. “We want to understand why people did not use their injector,” says Mr. Khalaf. With children, parents are often hesitant to use them. Maybe adults don’t take it with them, or don’t renew the prescription…”