SKIN PRICK TESTING
Skin prick tests (Allergy Tests) are helpful in the diagnosis of immediate (IgE-mediated) allergic reactions to foods. Skin prick testing involves pricking the skin with a specialised device through a drop of allergen. The test is then measured after 15 minutes. The child sits independently or in the parent’s lap with the left forearm supported by a pillow. The parent assists by holding the arm at the elbow.
A test is considered positive if a wheal (hive) reaction occurs at the test site. After the test is read, the results and its significance for your child will be explained to you during the consultation.
A child with a “high positive” skin test result is not more likely to develop anaphylaxis; similarly, a child with a “low positive” skin test result is not less likely to develop anaphylaxis. The risk of anaphylaxis is difficult to predict, and is likely to depend on several factors, including (a) past anaphylaxis, (b) amount of food allergen ingested and (c) presence and severity of co-existing asthma.
Skin prick tests are safe. It is common to have skin itch and redness around the test site, which usually disappears within 24-48 hours. The risk of anaphylaxis is very low (around 1 in 3000 patients), and will be promptly managed if it occurs.
Prepare your child for the Skin Prick Test:
Tell your child that the allergy tests feel “prickly” and can be a bit uncomfortable. It can feel a bit sore or painful or just itchy and annoying and can even feel ticklish.
Do advise them that after the test is performed, even if it feels itchy it is important to not scratch while waiting for the next 15 minutes.
It is usually helpful to bring a toy, activity or book to distract them during this time.
You can also watch a short video with your child to prepare them for the skin prick test.