Written by Registered Dietitian Nishti
We are often asked how to test children who have a suspected allergy to cow’s milk protein (or other foods).
To answer this question, we first must differentiate between a delayed and an immediate allergy to cow’s milk, also known as IgE, and a non-IgE cow’s milk protein allergy. This blog explains the difference, including the symptoms so please read this first.
Validated Tests
Allergy tests alone can’t diagnose a milk allergy. Your clinician must take an allergy-focused history before deciding what foods to test for. We can not solely rely on just a positive or a negative result. An allergy-focused history is key.
There are only two scientifically validated tests to help diagnose an IgE allergy to milk (or other food allergy). These are:
- Skin prick tests (SPT’s)
- Specific IgE antibody blood test (sIgE)
With SPT’s, results are obtained within 20 minutes whereas the results of a blood test can take a few days to come back.
An important note to mention about SPT is that the larger the wheel size, the higher the chances of a reaction. However, a large wheel size does not predict the severity of a reaction.
Please watch this video from ITV news where Nishti explains allergy testing.
The issue with allergy testing
It is important to understand what type of allergy your child has because if they have a delayed type of cow’s milk allergy, then there is no scientific reason to test for it other than through the use of an elimination/reintroduction diet (more about this below). In simple words: We cannot use allergy tests to test for delayed cow’s milk allergy. We can only eliminate it (take it out) from the diet and then, if symptoms have improved, reintroduce it back into the diet.
Also, allergy tests cannot predict the severity of an allergic reaction. A test can only predict the likelihood of a future allergic reaction.
Here’s how to test for non-IgE milk allergy
On YouTube, we have detailed videos that explain the steps required to diagnose your child with a delayed allergy to cow’s milk.
For formula-fed infants please watch this video.
For breastfed infants please watch this.
For children with immediate symptoms
If your child has immediate reactions to milk (or other foods) then they must see a paediatrician in allergy. Here at Nishti’s Choice, we recommend Dr Costa.
We provide expert help and advice to families with an allergy baby. To book a no-obligation chat please visit the booking page.
References:
.Fox, A., Brown, T., Walsh, J. et al. An update to the Milk Allergy in Primary Care guideline. Clin Transl Allergy 9, 40 (2019). https://doi.org/10.1186/s13601-019-0281-8
Luyt D, Ball H, Makwana N, et al. BSACI guideline for the diagnosis and management of cow’s milk allergy. Clin Exp Allergy. 2014;44(5):642-672. doi:10.1111/cea.12302