Patient information · Paediatrics
Cow's milk allergy in babies
over-diagnosed and under-diagnosed, in different families
Cow's milk protein allergy affects around 2 to 3% of infants. It is also frequently blamed for ordinary reflux, colic and unsettled behaviour, which leads to unnecessary formula changes and needlessly restricted diets. Getting the diagnosis right matters in both directions.
Call 999 if your baby has
- swelling of the lips, tongue or face, or difficulty breathing
- wheeze, noisy breathing or persistent cough after a feed
- sudden pallor, floppiness or collapse
- widespread hives with vomiting
- profuse repeated vomiting with lethargy hours after a feed
Immediate allergic reactions usually begin within minutes to two hours of a feed. If an adrenaline auto-injector has been prescribed, use it into the outer thigh and call 999. In an emergency go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
Two different patterns
- Immediate (IgE-mediated) — within minutes to two hours: hives, swelling, vomiting, wheeze, and rarely anaphylaxis. Diagnosed with skin prick or blood testing.
- Delayed (non-IgE) — hours to days later: reflux and vomiting, loose or mucousy stools sometimes with blood, colic-like distress, worsening eczema, food refusal, faltering growth. No blood test diagnoses this — it is diagnosed by removing milk and then reintroducing it.
Reintroduction is part of the diagnosis, not an optional extra
Removing milk and seeing improvement proves very little on its own — babies change week to week, and many settle anyway. The diagnosis is only confirmed when symptoms return on reintroduction. Skipping that step is how children end up on specialist formula for a year or more without ever having had the allergy. It is worth doing, under guidance.
If you are breastfeeding
- Keep breastfeeding. Only a small amount of milk protein passes into breast milk, and stopping is almost never the answer.
- The mother excludes all cow's milk protein for two to four weeks, then reintroduces to see whether symptoms return.
- A breastfeeding mother excluding dairy needs 1000mg calcium and 10 micrograms vitamin D daily, and dietitian support.
- Do not exclude multiple food groups speculatively — this risks maternal nutrition and rarely helps.
If formula feeding
- An extensively hydrolysed formula is first line for most infants.
- An amino acid formula is used for severe cases, faltering growth, or where hydrolysed formula fails.
- Soya formula is not recommended under six months. Partially hydrolysed, lactose-free, goat's and sheep's milk formulas are not suitable — lactose intolerance is a different condition entirely and is rare in babies.
- Specialist formulas taste unpleasant. Introduce gradually over several days, mixing increasing proportions.
Outgrowing it
Reintroduction follows a structured milk ladder, starting with well-baked milk in biscuits — baking alters the protein so it is tolerated first — and progressing over months. This should be planned rather than improvised, and children with immediate or severe reactions should only be challenged under specialist supervision.
What it is not
Not lactose intolerance, which is rare in infants and quite different. Not reflux by itself — posseting is normal and most reflux needs no treatment. Not colic on its own. Not a reason to switch formula repeatedly, which delays finding the real cause and unsettles feeding further.
Why come to us. This needs time and follow-up, which is exactly what a ten-minute appointment cannot give. We offer unhurried paediatric appointments seven days a week, allergy testing performed on site for the immediate type, weight and growth monitoring so that nutrition is not compromised, a structured elimination and reintroduction plan rather than an open-ended exclusion, and dietitian input arranged through our CQC-registered partners.
Diagnosed properly, and reintroduced safely
Paediatrics and allergy testing on site, seven days a week.
Tower Bridge Hospital London
97–99 Whitechapel Road, London E1 1DT
WhatsApp 07903 284 189
info@mhwclinic.co.uk
Open Mon–Sat, 9am–7pm (closed Sundays until September)
In an emergency
Call 999, or go to the Royal London Hospital Emergency Department, Whitechapel Road, London E1 1FR.
When we are closed and it is not an emergency
Call NHS 111 or visit 111.nhs.uk.