Deadly allergy from unknown cause not always well treated: study

An estimated 2.5 million Canadians live with anaphylaxis, that is the possibility they could die from an extreme allergic reaction, but some of them don’t know what the trigger is. Others may be tested and find out they are severely allergic to things like a particular food, insect stings, latex or exercise.

A new study from the McGill University Health Centre looked at nearly 4,000 cases of anaphylaxis and found that 7.5 per cent of them were due to an unknown cause. It also found there were “significant discrepancies in treatment and follow up” of these patients.

Anaphylaxis can occur within minutes and requires quick transportation to hospital. (iStock)

Children are treated differently 

What often happens in a first severe allergic reaction is that a person’s face may swell, they may have difficulty breathing, break out in hives, suffer vomiting or diarrhea. They must rush to a hospital emergency room and be treated quickly. Afterwards, if a particular trigger is suspected, the patient would be referred to an allergist to confirm the cause. An epinephrine auto injector would be prescribed as emergency medicine to stall a future reaction and give the person time to get to a hospital for treatment.

What this study found was that among cases where the cause of the allergy was not known, almost one fifth of patients were not prescribed the life-saving auto injector and only 56 per cent were referred to an allergist. Children were more likely to be prescribed the auto injector and be referred than were adults.

Finding the trigger is important

Of the patients who were assessed by an allergist, a trigger for the reaction was found in 38 per cent of the cases. This makes it easier for a patient to avoid the trigger and avoid a serious reaction in future.

The study concludes there is a need for clear guidelines and educational programs for better diagnosis and management of deadly allergies when the cause is unknown. It was published in The Journal of Allergy and Clinimal Immunology: In Practice.