At what age can an allergy test be taken and how is this test carried out? We asked our questions to Dr. Jacques Hébert, allergist at the Center for Applied Allergy Research in Quebec.
What are the first signs of an allergy in babies or children?
An allergy can manifest itself in many ways. In the case of a food allergy, for example, the child could have skin symptoms (eczema, hives, red patches), digestive symptoms (vomiting, recurrent diarrhea, persistent constipation) or respiratory (asthma, difficulty breathing, swelling of the lips, tongue and throat). Young babies can be irritable and cry a lot. In the case of a respiratory allergy, your child could have an itchy and runny nose (liquid secretions, without fever). Watery eyes and itchy, sneezing are also common.
Warning signs and the severity and intensity of symptoms can vary from child to child, and sometimes from attack to attack in the same child.
From what age can you take your child to see an allergist?
There is no age, since the allergy test is also effectivein a two-week-old child than in an adult. As soon as there is a doubt of an allergy, it is therefore very advisable to have your child pass an allergy test. The faster the intervention, the more suffering and complications are avoided.
Is it possible to predict an allergy?
No, even if heredity has a role to play: in fact, when a family member (parents, brother or sister) has a form of allergy, the risk that the child develops an allergy increases. The environment also has a role to play. For food allergies, a delay in introducing a food could also be the cause.
Are there multiple ways to test for allergies?
In the vast majority of cases, skin tests are done. It is also possible to have a blood test.
How is the test?
The doctor advises and explains to the child what he is going to do to prepare him well. Throughout the course of the skin test (small bites), the doctor talks to the child and asks him to look him in the eye. The doctor places drops on the child's arms and then injects them so that the drops enter the skin, with a sterile needle. These small bites look like an insect bite. It is not painful. Afterwards, the child must wait about thirty minutes to see if there are any reactions. When there is a reaction, we may see swelling, redness or itching on the arm:the test is then considered positive. If there is no reaction, it is negative.
While waiting, the child's arms may itch a little, but the child should not scratch. After half an hour, the doctor sees the child again and measures the swelling: he will thus determine whether there is an allergy or not. Following the diagnosis, the doctor explains the medication and treatments prescribed, if applicable.
Is it necessary to do several tests?
You have to do one test per element to be tested. Some allergies require a review and, depending on the condition, it is possible to repeat the tests once a year.
Can the child have a strong allergic reaction following this test?
No. The reaction, of a cutaneous nature, will remain localized to the place where the test was done.
Are the results 100% reliable?
We estimate the positive predictive value at 50%: it therefore happens that a test which was intended to be positive turns out to be negative, during a subsequent examination. However, the negative value of a test is 97%, so a negative result is very reliable.
Are the results final?
Tests are a snapshot of the situation: it can change. Indeed, we are not born allergic, and allergies can develop and change, at any age.
Is it possible to "cure" an allergy?
Sometimes an allergy disappears, like certain food allergies triggered at a very young age. TheBovine protein allergies, for example, tend to disappear after 1 year of age.
In short, if we believe that our child has an allergy, what are the steps to follow?
To conclude to a food allergy, you must first identify the allergy and prove it by tests, with a doctor. Thanks to a medical diagnosis, it is then possible to exclude other he alth problems that could manifest themselves through similar symptoms, such as food intolerances. When the allergy is identified, it is treated according to the recommendations of the allergist or doctor. It is necessary to carry out a control of the environment and to eliminate the allergens present in the house (cat, dust, dust mites…) For food, we avoid the consumption.
Are allergy tests covered by the Régie?
Thank you to Dr. Jacques Hébert, allergist at the Applied Allergy Research Center of Quebec, for answering our questions! You can consult it at 2590 boulevard Laurier, in Quebec, 418-659-7741