Allergy Testing for Kids: What to Expect

Allergy tests are most useful when they answer a specific question, such as "Is peanut what caused that reaction?" or "Is it the cat or the pollen?" Used without a clear question, they often find "allergies" that are not real and lead to foods being cut unnecessarily. Here is how testing works and when it makes sense.

When allergy testing helps

• Hives, swelling, vomiting, or breathing trouble shortly after eating a specific food
• Year-round or seasonal nose and eye symptoms that are not controlled with daily medicine
• Asthma, when finding a trigger (dust mites, pets, mold, pollen) would change the plan at home
• Moderate to severe eczema that does not improve with good skin care, when a food trigger is suspected
• A reaction to an insect sting beyond the area of the sting
• Deciding whether a child might benefit from allergy shots or tablets

When testing usually does not help

• Broad food panels without symptoms. The AAP warns that food testing without a history of reactions often returns positive results for foods a child eats without problems.
• IgG food sensitivity tests sold online or in some clinics. These are not valid for diagnosing allergies.
• Before introducing peanut to most babies. Most infants can start peanut and other allergens at home around 4 to 6 months. Ask us first if your baby has severe eczema or a known egg allergy. Our food allergy guide covers early introduction.
• Frequent colds. Young children commonly get 6 to 8 colds a year. A runny nose with fever and body aches is usually an infection, not allergy.

The two main tests

Skin prick test

An allergist places tiny drops of allergen on the back or forearm and lightly pricks the skin with a plastic tool. It feels like a quick scratch, not a shot. A raised, itchy bump after 15 to 20 minutes suggests sensitivity. Antihistamines must be stopped several days ahead because they block the reaction.

Blood test (specific IgE)

One blood draw can check several allergens at once. Results take a few days. Blood tests are a good choice for children with widespread eczema, skin conditions that make skin testing hard to read, or who cannot stop antihistamines.

Oral food challenge

The most accurate way to know if a child is truly allergic to a food is to eat it under medical supervision, in gradually increasing amounts, at an allergist's office. It is often used to confirm that a child has outgrown an allergy or that a positive test does not matter.

How to prepare your child

• Write down what happened during any reaction, what was eaten, and how long it took to start.
• Bring photos of rashes or hives if you have them.
• Ask the allergist's office which medicines to pause and for how long.
• For younger children, explain that the skin test feels like "tiny scratches and itchy bug bites."
• Bring a tablet or book; skin testing visits often take an hour or more.

After the results

Results are interpreted together with your child's history. A plan may include avoiding a confirmed food, an epinephrine auto-injector and written emergency plan for food allergy, daily allergy medicine (see our Zyrtec and Claritin dosing guide), steps to reduce dust mites or pet dander at home, or allergy immunotherapy.