Cow's Milk Allergy in Children

🔍 When to Suspect

Symptoms appear after cow's milk ingestion: immediate (rash, vomiting, wheeze) or delayed (GI upset, eczema)

From the full topic in The Ocean Library: Cow's Milk Allergy in Children

🧭 When to suspect

Suspect cow’s milk protein allergy (CMPA) in an infant or young child with skin, gastrointestinal or respiratory symptoms that begin after the introduction of cow’s milk-based formula, the start of weaning, or – in a breastfed baby – in response to maternal dairy intake. It is a reproducible, immune-mediated reaction to one or more cow’s milk proteins, affecting roughly 2–3% of infants, and it is the most difficult food allergy to diagnose because its features overlap heavily with normal infant behaviour and with reflux and colic.

The single most useful distinction is timing, which separates the two mechanisms and drives the whole pathway.

Feature	IgE-mediated (rapid onset)	Non-IgE-mediated (delayed onset)
Onset after ingestion	Minutes, and almost always within 2 hours	Delayed – 2 to 72 hours, occasionally several days
Typical features	Urticaria, angio-oedema, acute vomiting, wheeze, rhinorrhoea, and rarely anaphylaxis	Atopic eczema, reflux/GORD, colic, diarrhoea or constipation, blood or mucus in stool, food refusal, faltering growth
How it is confirmed	Specific IgE or skin-prick test, interpreted with the history	Clinical – diagnostic elimination then planned reintroduction; no useful blood test

Mixed pictures occur, and the absence of any single feature does not exclude CMPA. A personal or family history of atopy (eczema, asthma, allergic rhinitis, food allergy) raises the probability.

Source: NICE CG116 · iMAP (MAP 2019) · BSACI

⚠️ Common pitfall – over-diagnosing CMPA Reflux, posseting, colic and an unsettled, crying baby are physiological and extremely common in well, thriving infants – the UK has the highest rate of non-IgE CMPA diagnosis in Europe, much of it likely over-labelling driven by symptom overlap. Before reaching for a hypoallergenic formula, review feeding and offer reassurance, and reserve a dairy-elimination trial for a genuine cluster of suggestive symptoms. A useful discriminator: effortless posseting in a content baby points away from allergy, whereas the CMPA infant who vomits is usually miserable, irritable and back-arching.

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