When you're breastfeeding a baby with food allergies, you know the struggle of hearing wishy-washy answers, like “it might be…” or “it could be...”
It’s not enough.
It doesn’t relieve your concerns. You need to see definite results, and this uncertainty can’t help your baby feel better. This is when testing for food allergies makes sense.
Unfortunately, it’s a bit complicated.
First, it’s important to understand what food allergies are versus what they aren’t. Food allergies cause an immune response. Food intolerances are a digestive response, like when lactose intolerance causes gas, indigestion, and bloating. Allergies, especially for infants, often cause serious reactions and require special attention. (That’s why we’re all here, right?)
At Free to Feed, our team helps parents navigate their food allergy journey with scientific resources, real support, and guidance every step of the way.
Today, we’re diving into different types of food allergy testing in babies. We’ll be giving it to you straight, which means sometimes you won’t hear the most desirable answers. But we believe honest dialogue based on research makes a real difference. It’s why we’re here – to change the food allergy community for families like yours.
Read on to learn more about the tricky nature of food allergy testing, and remember you’re not alone on this journey.
1. Testing Infant Food Allergies with The Skin Prick Test (SPT)
It’s important to understand the different types of food allergies when talking about testing. The two we’ll focus on are IgE-mediated and non-IgE food allergies. (Read more on them here.)
IgE food allergies can cause a life-threatening anaphylactic response and show a reaction quickly.
Non-IgE allergies can be utterly confusing since they don’t produce excess IgE antibodies and can show both immediate and/or delayed reactions. They continue to be controversial in the medical community. Both impact your baby and family when food allergies are concerned.
Skin Prick Test
When your baby has an IgE-mediated food allergy, the immune system responds by producing IgE antibodies. They build up over time and can be detected with a skin prick test (SPT). The test pricks or scratches a tiny amount of the food allergen into the skin. Depending on how the skin reacts, the test yields a negative or positive result.
Since non-IgE mediated allergies don’t produce these antibodies, the SPT won’t show you anything.
The Good: Skin prick tests give you some information, which as a food allergy parent seems like a breath of fresh air. Any information is better than the continued guessing game.
The Bad: First, skin prick testing in infants isn’t typically conducted until 6 months of age due to accuracy.  This makes it incredibly challenging for parents of newborns or children under 6 months.
Second, the accuracy of the test — even when your baby is 6 months or older — isn’t 100%. We know, this isn’t sounding great right now, but we don’t sugarcoat anything. For example, if you received a “false positive” on a test, you could be avoiding food without needing to. But the third way of testing can give you some hope, keep reading.
Third (yup), SPT don’t pick up non-IgE- food allergies since they don’t produce IgE antibodies. This is a HUGE fail for all the families with non-IgE mediated food allergies.
Conclusion: Skin prick tests can give you some insight into your child’s food sensitivities. But they only work for IgE allergies, and only sometimes. This test by no means offers a solid answer for every family.
2. Blood Tests For Babies With Food Allergies
Commonly referred to as the Radioallergosorbent Test (RAST) and similar to SPT, a blood test measures the levels of IgE antibodies in your baby’s blood.
The Good: Blood tests give an understanding of how the body responds to allergens on very specific levels and test a wide range of allergens.
The Bad: Some IgE antibodies are normal in your body (there's a threshold) — so showing up on a blood test they may be labeled as “sensitivity” and not a “true allergy.” We’re not a fan of these terms for multiple reasons, the biggest being is it’s not safe for the food allergy community. There ARE different types of food allergies — including non-IgE and mixed.
Hint: Be careful of the numerous food allergy testing kits available for purchase online that do not have clinical evidence of accuracy.
3. The Oral Food Challenge (OFC)
The basics of an OFC is to give a pre-measured amount of an allergen to your baby (usually small to start), and see if they react. We know, that sounds terrifying.
This is one of the biggest services we offer to our families — assisting them in safely reintroducing triggers to their babies. It’s a scary time but with the right guidance, you can feel prepared.
The Good: First, OFC helps you determine what the allergy is and when your child has outgrown them. This testing method gives you vital information on your diet and safety.