Breastfed baby with suspected cow's milk allergy: should the mother avoid certain foods?

Before the mother avoids foods, clarify two things

When a breastfed baby has eczema, spits up, has diarrhoea or cries a lot, parents often think of cow's milk allergy. But these signs are common and have many causes. Cow's milk allergy is a reaction caused when the immune system mistakenly treats milk protein as harmful. Not every discomfort can be blamed on it.

Milk protein in the mother's diet may pass small fragments into breast milk. But whether to avoid foods cannot be decided by guessing. First, a doctor should assess the baby's signs to judge whether cow's milk allergy is possible, and then decide whether to try food avoidance. Stopping dairy widely without assessment may affect the mother's nutrition and may not help the baby.

If the doctor suggests a trial of food avoidance, how to observe and record

The avoidance plan should be made by a doctor. It includes which foods to avoid, for how long, and how to reintroduce them later. What parents can do is observe carefully. Record the type of symptom, when it appears, how long it lasts, how severe it is, and what the mother ate that day.

You can record it as follows:

• Symptoms: rash, vomiting, diarrhoea, blood in stool, crying, weight gain and so on. Write each one down.
• Timing: how long after feeding the symptom appears, and whether it relates in time to what the mother ate.
• Severity: describe as mild, moderate or severe. Take photos to record changes in the rash.
• Diet: record intake of dairy and other suspected foods.

During avoidance, do not widen the range on your own, and do not keep it going long term without review.

Avoidance is not better the longer it lasts; do not decide replacement feeding yourself

If the baby's symptoms clearly improve after a trial of avoidance, that does not mean avoidance can continue forever. Doctors usually arrange staged assessments to judge whether to continue and how to adjust later. Long-term avoidance without guidance may leave the mother undernourished and may make the baby miss the chance to build tolerance.

When breast milk is not enough or the doctor judges that replacement feeding is needed, what to use and for how long should be decided by the doctor based on the baby's age and situation. Parents should not buy special formula or switch to other milks on their own, and should not apply one avoidance plan to the next child.

When to see a doctor

If the following signs appear, see a doctor as soon as possible. Do not just adjust the diet at home:

• The baby vomits or has diarrhoea soon after feeding, or there is blood in the stool.
• The rash is widespread, oozes, or comes with obvious itching that affects sleep.
• There is wheezing, difficulty breathing, hoarse voice or swelling of the lips.
• The baby is listless, responds weakly, looks pale, or weight gain is clearly behind.
• The baby's symptoms do not improve after the mother avoids foods, or they worsen again after improving.

These signs are not necessarily cow's milk allergy, but they need a doctor's face-to-face assessment.

Bring the questions to the doctor, do not carry them alone

Before the visit, organise your records: the timeline of symptoms, changes in the mother's diet, and the avoidance already tried and its effects. The doctor will use this information to judge and, if needed, arrange further tests. Parents should not demand or refuse a test on their own. List your questions and ask them clearly face to face.

Managing cow's milk allergy is a long-term process, and the plan will be adjusted as the baby grows. The mother does not need to guess alone, and should not treat food avoidance as the only tool. Following the doctor's plan and having regular reviews is the safer approach.

This article is for general information only and is not medical advice. Please follow your doctor's instructions.