Cow's milk allergy
Allergy to cow's-milk protein (distinct from lactose intolerance).
About cow's milk allergy
Cow's-milk allergy is one of the most common food allergies in babies and young children, and it is important to distinguish it from lactose intolerance, which is a digestive problem with the milk sugar lactose and not an allergy at all. Milk allergy is an immune reaction to milk proteins such as casein and whey. Many cases are IgE-mediated and immediate, while some are non-IgE reactions that come on more slowly; the immediate type is the focus here. Milk is a named allergen on UK food labels.
In IgE-mediated milk allergy, symptoms usually begin within minutes and can include hives, swelling, vomiting, wheezing and, at the severe end, anaphylaxis with breathing difficulty or collapse. Non-IgE reactions tend to cause delayed symptoms such as eczema, reflux, colic and altered stools. Many children outgrow milk allergy, and some who react to fresh milk tolerate milk baked into foods, but this should only be explored under medical guidance. Cow's-milk protein also cross-reacts with goat's and sheep's milk, so these are not usually safe alternatives.
Diagnosis is made by an allergy specialist using the history with skin-prick or specific-IgE blood tests for the immediate type, and supervised food challenges where needed. Management means avoiding milk and reading labels for milk, casein, whey and lactose, with suitable substitutes and dietitian support. People at risk of severe reactions carry an adrenaline auto-injector. A severe reaction is a medical emergency: use adrenaline and call 999.
Common triggers
- Milk, cheese, butter and cream\nYogurt and ice cream\nMilk powder in processed foods
Symptoms
- Itching or tingling in the mouth
- Hives, itching or eczema
- Swelling of the lips, face, tongue or throat
- Stomach cramps, nausea, vomiting or diarrhoea
- Wheezing or trouble breathing
- In severe cases, anaphylaxis
Avoidance & management
- Read ingredient labels every time
- Ask about ingredients and cross-contamination when eating out
- Keep the food out of shared cooking areas
- Carry prescribed antihistamines or an adrenaline auto-injector
- Seek emergency help for any severe reaction
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.