Think your baby is allergic to cow’s milk?

When young infants develop vomiting, diarrhea, and fussiness, some of them are diagnosed as having an allergy to cow’s milk protein. When that diagnosis is made, babies on formula have to switch to a specialized formula — and the mothers of breastfeeding babies have to eliminate all dairy from their diets.

The problem is that specialized formulas are very expensive, which can be a real burden for families. And eliminating all dairy from your diet can be very difficult (it’s surprising how many foods have some dairy in them), leading some mothers to stop breastfeeding.

If every baby that was diagnosed with cow’s milk allergy definitely had it, this would be unfortunate but unavoidable. However, many — if not most — of the babies who get this diagnosis don’t have it at all.

The two types of allergy to cow’s milk

There are two kinds of cow’s milk allergy. One of them is mediated through a type of immunoglobulin called IgE, which causes classic food allergy. This kind is easier to diagnose, as children have more classic symptoms of allergy such as rashes, facial swelling, or flushing. There are also blood tests that can help make the diagnosis.

The other kind is not mediated through IgE, and is tougher to diagnose with certainty.

Babies with non-IgE mediated cow’s milk allergy can have various symptoms, such as vomiting, fussiness during or after feeding, diarrhea, or blood in the stool. The problem is that lots of babies without allergy can have vomiting, fussiness, or diarrhea — and there are other reasons why babies might have blood in the stool, including having a small cut in the anus. The only way to definitively diagnose non-IgE mediated allergy is to eliminate all dairy, see if the baby gets better — and then reintroduce dairy again and see if the symptoms come back.

For lots of understandable reasons, many doctors and parents don’t want to do that reintroduction once a baby gets better — but the baby getting better may have nothing to do with the diet change.

Cow’s milk allergy is uncommon

According to a special communication published in JAMA Pediatrics, while 14% of babies are reported to have cow’s milk allergy, only about 1% actually do have it.

As for the diet restrictions for breastfeeding mothers, the authors report that those are likely not necessary, even if there is an IgE-mediated allergy. So many mothers are putting their nutrition at risk, or stopping breastfeeding, for no good reason.

It’s also worrisome that in 81% of the published guidelines on cow’s milk allergy, the authors of the guidelines reported a conflict of interest with formula manufacturers. This does not mean that the guidelines aren’t good or accurate, but it’s troubling that the formula manufacturers are supporting so much of the research.

If your baby has been diagnosed with cow’s milk allergy, and you have changed your baby’s diet or your own, don’t stop these changes without talking to your child’s doctor. But definitely talk to the doctor, and be sure that you understand exactly why your baby has the diagnosis and whether any further evaluation makes sense.

If you have a fussy baby that has problems with feeding or pooping, such as diarrhea or blood in stools, be sure you ask lots of questions if your doctor brings up cow’s milk allergy. Be sure that it is the right diagnosis for your child, especially before making any changes. Remember that fussiness, and problems with feeding and stools, are very common in little babies — and the majority get better with nothing more than the passage of time.

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