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Cow's milk protein allergy in infants
Cow's milk protein allergy is the commonest food allergy in infancy, with an IgE-mediated form (rapid reaction, up to anaphylaxis) and non-IgE forms (proctocolitis with blood in the stool, FPIES with repetitive vomiting); treatment is removing the protein — maternal diet when breastfeeding or an extensively hydrolysed formula — and most children outgrow it.
Why it matters in the exam
Three pictures recur. A 6-week-old breastfed infant who looks excellent and gains weight, with streaks of blood and mucus in the stool — allergic proctocolitis; treatment is removing dairy from the mother's diet, and the blood clears within days to weeks. An infant who starts formula and within minutes develops urticaria, vomiting and swelling — IgE-mediated allergy, and the work-up is skin tests or specific IgE. An infant who vomits repeatedly 1–4 hours after a feed, pale and lethargic, sometimes to the point of shock, without skin signs — FPIES.
In FPIES there is no IgE, skin tests are negative and the diagnosis is clinical; acute treatment is IV fluids and ondansetron, not adrenaline. In the non-IgE form the diagnosis is made by 2–4 weeks of elimination and a supervised re-challenge. For formula, the first choice is extensive hydrolysis; amino acid formula is kept for severe reactions or failure. Goat's milk is not an alternative because of cross-reactivity, and soy-based formula is avoided before 6 months of age.
It is important to separate this from lactose intolerance — an enzyme disorder, not an allergy, and rare as a primary form in infants — and from "wind" and physiological reflux. A mother who removes milk from her diet needs a calcium supplement. Most children with the non-IgE form outgrow it by age 1–3, and a large proportion of those with the IgE form by age 5; gradual return to milk is sometimes done with a "milk ladder" of baked products.
Key points
- Milk allergy is the commonest food allergy in infancy.
- IgE: minutes; FPIES: hours of vomiting; proctocolitis: blood in the stool in a healthy infant.
- Diagnosis in the non-IgE forms: elimination and re-challenge.
- Extensively hydrolysed formula as the first choice.
- Most children outgrow the allergy.
Summary table
| Form | Timing and picture | Diagnosis | Treatment |
|---|---|---|---|
| IgE-mediated | Minutes to two hours: urticaria, vomiting, angioedema, anaphylaxis | Skin tests, specific IgE | Strict avoidance; adrenaline auto-injector |
| Allergic proctocolitis | Healthy breastfed infant with blood and mucus in the stool | Clinical; improves on elimination | Remove dairy from the mother's diet, continue breastfeeding |
| FPIES | Repetitive vomiting 1–4 hours after eating, pallor, lethargy, sometimes shock | Clinical; IgE negative | IV fluids, ondansetron; avoid the food |
| Milk protein enteropathy | Chronic diarrhoea, failure to thrive | Elimination and re-challenge | Extensively hydrolysed formula |
| Formula for the non-breastfed infant | — | — | Extensive hydrolysate; amino acid formula for severe reactions; not goat's milk |
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Sources
- ESPGHAN Position Paper: Diagnosis and Management of Cow's Milk Protein Allergy in Infants, 2024 update — Diagnostic elimination and challenge, formula choice
- International consensus guidelines for the diagnosis and management of food protein-induced enterocolitis syndrome (FPIES), 2017 — Acute FPIES management
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Food Allergy and Adverse Reactions to Foods
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.