Secondary anaphylactic reactions may occur in some children, new study finds

by Alicia French 

Any parent who has a severely allergic child knows the anxiety and stress that come with preventing serious reactions. Anaphylactic reactions occur when a person is exposed to an allergen, like peanut butter or a bee sting, and the reaction can be deadly. As if that isn't scary enough, a new study has found that secondary reactions may occur hours later, and some children may be more susceptible than others.

Ontario researchers just published a study in Annals of Allergy, Asthma & Immunology that looked at 484 children treated for anaphylaxis. The goal of the study was to find out how common biphasic reactions were and what some of the associated risks were.

Children who didn't receive treatment immediately, children aged 6 to 9 or children who required more than one dose of epinephrine were more likely to suffer a secondary reaction. 15 per cent of the children in the study experienced a second anaphylactic reaction.

The study's authors admit that the findings are preliminary and further research needs to be done to develop a better treatment protocol. However, the results are something that parents with severely allergic children should pay attention to. Particularly if they receive treatment and are sent home from the hospital quickly.

The authors want the takeaway message for these results to be that parents should treat a reaction immediately. "Treat an allergic reaction with epinephrine, and treat it early. And after that, seek help. That's the key message for parents," Dr. Waleed Alqurashi told CBC News.

Another study found that biphasic reactions occurred in 20 per cent of patients. While secondary reactions are often more mild, they can also be just as severe or more so than the first. In addition, epinephrine may not be sufficient for a secondary reaction. Intubation may be required to clear the airway.

The majority of secondary reactions occur within four to 10 hours after the initial reaction. Parents of young children in particular should monitor their children closely after an anaphylactic reaction, especially if they are no longer under medical supervision.