Findings of a new study have showed that about 15% of children who experience a severe allergic reaction that involves anaphylaxis have the likelihood of having second reaction hours after the first.

The study suggests parents and doctors to be careful about this type of two-stage or biphasic anaphylactic reaction. Children aged six to nine, children who need more than one dose of epinephrine to control their reaction and children who do not get treatment initially are among the ones who can develop biphasic anaphylaxis.

Adults can suffer from biphasic anaphylactic reactions, but the focus of this study was only on children. Published in the journal Annals of Allergy, Asthma and Immunology, the study is the largest to have looked at biphasic anaphylaxis.

For the study, the researchers from the Children's Hospital of Eastern Ontario looked at the records of 484 children who had received treatment for anaphylaxis at CHEO or at the Hospital for Sick Children in Toronto.

The study was aimed at determining how common biphasic reactions were and understanding what ways could help predict children at the highest risk of a second delayed reaction.

Dr. Waleed Alqurashi, the first author of the paper, said an allergic treatment should be treated with epinephrine and the treatment should be provided as early as possible. “And after that, seek help. That's the key message for parents”, said Alqurashi.