Synopsis
Recognise immediate and delayed cow's-milk protein allergy, distinguish it from lactose intolerance and common infant symptoms, confirm diagnosis with the appropriate test or elimination-reintroduction sequence, prescribe nutritionally complete substitutes and prevent unsafe restriction or home challenge.
- Cow's-milk protein allergy is immune mediated. Lactose intolerance is not milk allergy and is uncommon as a primary disorder in young infants; lactose-free formula still contains cow's-milk protein.
- IgE-mediated allergy usually produces reproducible symptoms within minutes to 2 hours: urticaria, angioedema, wheeze, cough, vomiting, hypotension or collapse.
- Non-IgE allergy is delayed over hours to days and may cause eczema, diarrhoea, constipation, blood or mucus in stool, vomiting, reflux-like distress or faltering growth; these symptoms are nonspecific.
Key red flags
Stridor, wheeze, persistent cough, tongue swelling, collapse or altered responsiveness after milk is anaphylaxis until proved otherwise.
Investigation priorities
Estimate mechanism and pre-test probability before testing or elimination.
Resolve diagnostic uncertainty or reassess tolerance in a controlled setting.
Management branches
Milk causes rapid objective skin, respiratory, gastrointestinal or circulatory symptoms.
- Treat anaphylaxis immediately with intramuscular adrenaline and emergency services.
- Avoid milk, obtain allergy testing through an appropriately competent service and provide a written emergency plan.
Key medicines
Adrenaline 1 mg/mL intramuscular injectionSuspected anaphylaxis: 0.01 mL/kg intramuscularly into the anterolateral thigh, maximum 0.5 mL; repeat after 5 minutes if airway, breathing or circulation problems persist.