About allergies and allergens
Up to 10-15% of all children may have allergic tendencies. Allergy-prone children can either develop asthma, nasal allergies, eczema and/or food allergies. An allergy develops when a person’s body has a bad reaction to a particular substance or product that’s normally harmless, such as cow’s milk protein or pollens.
The substance that causes the allergic reaction is called an allergen. Allergens can enter the body when they’re eaten, touched, inhaled or breathed in. When the body perceives the allergen as something harmful, it tries to protect itself by making antibodies which attack the allergen. In the process, the person experiences various allergic symptoms that can range from mild to severe.
About allergy tests
Allergy testing helps us determine exactly what a person is allergic to by detecting whether a person has developed an antibody against a tested substance such as a specific food, airborne allergen or a medication. The easiest and most common way to do this is the “Scratch Test”, a simple and relatively painless procedure. A series of drops, each containing a specific antigen, is placed on a child’s forearm. Next, with a small needle, the area of skin at each drop is pricked very gently. After a 10-minute waiting period, if there is an allergy to a specific substance, a small bump will develop at the site of the scratch. The size of the bump, and the size of the surrounding redness, indicate how much a child is allergic to the specific substance tested.
In general, the test is very safe and does not induce an allergic reaction in the child, other than a local one at the site of the scratch. However, we generally do not perform the test if an asthmatic child has active symptoms at the time of the testing. Allergy tests can be performed at any age. But when testing for respiratory allergens, I believe the tests are more reliable in children five years of age and older. For foods, such as milk protein or peanuts, we test at any age. Allergy tests can help us identify what specifically is causing an allergic reaction or worsening a child’s asthma.
In the case of a food allergy, the test can determine whether a specific food has to be avoided in the diet. In the area of pollen allergies, the situation is more complex. There are different pollens which appear during different times of the year. Knowing which pollen a child is specifically allergic to, can help better prepare the child during a specific pollen season. Parents often wonder if allergy tests are helpful in determining the cause of eczema in their children. Disappointingly, the answer is usually no.
IT IS IMPORTANT TO NOTE THAT we do not test for cigarette smoke, as everyone is sensitive to the effects of second hand smoke.
Pediatrician DR.PAUL Roumeliotis is certified by the American Board of Pediatrics and Royal College of Physicians and Surgeons of Canada. The information provided above is designed to be an educational aid only. It is not intended to replace the advice and care of your child’s physician, nor is it intended to be used for medical diagnosis or treatment. If you suspect that your child has a medical condition always consult a physician.