Cow's Milk Protein Allergy: Signs in Children and Infants

A rash after feeding, vomiting, or loose stools in a baby may be signs of a food allergy. The cause may be cow's milk protein allergy: the child's immune system mistakes milk proteins for dangerous substances. Below — what it looks like, how it differs from intolerance, and what examinations are used.

What cow's milk protein allergy is and where casein comes in

Food allergy is an abnormal immune reaction to food: the immune system mistakenly identifies proteins in a product as dangerous. Cow's milk is on the list of the most common allergens alongside eggs, wheat, nuts, soy, peanuts, fish, and seafood.

Casein is one of the milk proteins, so the discussion of casein allergy falls within the same topic — allergy to milk proteins.

Why milk protein allergy occurs in infants

Why the immune system reacts in this particular way is not fully understood, but some foods cause reactions more often than others, and cow's milk is among the leaders in children.

The risk is higher with eczema and atopic dermatitis, asthma, other allergies, for example to pollen, and with allergies in relatives: genes play a role. Allergens penetrate more easily through dry, damaged skin.

Among modifiable factors, vitamin D deficiency, obesity, and an excessively "clean" environment are cited: allergies are more common in urban children. The prevalence of food allergy is about 6% in children and 1.5–2% in adults, while noticeably more people believe they have it.

Symptoms in newborns, infants, and older children

The reaction affects any part of the body and several areas at once: hives, redness, rash; vomiting, loose stools, cramps; cough, wheezing, itchy or stuffy nose, sneezing; swelling of the face, lips, and tongue, itching in the mouth, dizziness.

It usually begins within a few minutes to two hours after eating, but symptoms may also appear after days. In one child the reaction differs each time, and sometimes its severity depends on the amount of the product.

Allergy or intolerance — the difference is as follows:

• allergy is a reaction of the immune system, intolerance is not;
• with allergy there may be hives, swelling of the lips and face, vomiting, diarrhea, cough, wheezing — within minutes or a couple of hours;
• with intolerance — bloating, gas, abdominal pain, usually several hours after eating.

Reaction to formula and to breast milk

If symptoms appear after formula, the doctor determines whether the reaction may be related to milk protein.

Eliminating products from the mother's or baby's diet without consulting a doctor is not recommended: the decision is made by the doctor.

How cow's milk protein allergy is diagnosed

First comes the conversation: symptoms, family history, other allergies, examination. Then — examinations as indicated: skin prick test, blood tests for food antibodies, an elimination diet, when the product is temporarily removed and it is checked whether symptoms resolve, and an oral provocation test — the most accurate test for food allergy.

The doctor may ask you to keep a food and symptom diary — this helps to work out what triggers the reaction.

When urgent medical help is needed

A routine reason for a visit is suspected food allergy in a child. Most symptoms are not dangerous, but in some children the reaction is severe.

A rash or a single episode of vomiting is not in itself a reason to call an ambulance; 103 or 112 — if the child suddenly has swelling of the lips, mouth, tongue, or throat; breathing has become very rapid, wheezing has appeared, and he or she is gasping for air; the throat has tightened and swallowing is difficult; the skin, tongue, or lips have turned blue, gray, or pale; he or she is suddenly very lethargic, drowsy, or disoriented; has lost consciousness, gone limp, and is not responding as usual.

The text is for reference: it helps to prepare for an appointment and to understand what to ask about, but does not replace consultation with a doctor.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer