The most common types of allergy tests for children are skin prick tests, which can be done in a variety of ways. If these tests are not possible or may potentially harm the child, a radioallergosorbent test (RAST) may be performed. Elimination diets can be allergy tests for children that help to determine if any food sensitivities are present.
Skin prick tests help to determine what substances are causing an allergic reaction in a child. These allergy tests for children take a small amount of a single allergen and expose a child to it through the skin. The skin of the forearm or back is scratched, pricked, or punctured with a needle dipped in the allergen. In some cases, the substance is injected just underneath the skin.
Fifteen to 20 minutes after the test is performed, a round, itchy bump will appear if the child is allergic to the substance; this is caused by the immune system making antibodies in response to the allergen. The size of the bump can usually indicate the severity of the reaction. These allergy tests for children can typically be done with several different allergens in various locations on the skin. The doctor will usually number each skin prick site in conjunction with the allergen to determine which substances a child’s body responds to.
These allergy tests for children are usually performed by a doctor specializing in allergies, and the child is monitored by the doctor throughout the procedure. In rare instances, a severe allergic reaction can occur and may require quick medical intervention; when done under close observation, there is little risk to the child, however. Children taking certain medications will need to discontinue them for a short period before the test to obtain trustworthy results. These tests are considered accurate at a rate of 90%.
If a very strong allergic reaction is expected, if a child cannot discontinue medication long enough to undergo the test, or if a skin condition is present, a RAST may be used to test for allergies. Blood is drawn from the child and sent to a lab, where it is tested for allergic reactions to different substances. This test is considered just as accurate as other allergy tests for children, although it can take a few days to a several weeks to receive results.
When food allergies are suspected, doctors will often use elimination diets as allergy tests for children. All common allergy-causing foods are removed from the child’s diet, such as eggs, peanuts, shellfish, and soy, for four to seven days. If the previous allergy problem disappears, each food is slowly reintroduced into the child’s diet one at a time, with about a week between each. If or when the allergic reaction occurs, it is usually easy to determine which food poses the problem. This test is considered relatively accurate as long as processed foods with numerous ingredients are not consumed.