Human milk allergy is very rare. It happens when a baby’s body reacts to breast milk itself. Most feeding problems are caused by proteins from foods the mother eats, not the milk itself.
What You Should Know
- Very uncommon: Fewer than a few cases reported worldwide.
- More likely cause: Proteins from cow’s milk, soy, eggs, nuts, or other foods can pass into breast milk and cause reactions.
- Misdiagnosis happens: Many babies thought to have human milk allergy are actually reacting to dietary proteins in the milk.
Signs and Symptoms
If a baby might have a reaction to milk, look for:
- Rash, hives, or swelling after feeding
- Vomiting or diarrhea
- Blood in the stool
- Wheezing or trouble breathing (rare, serious)
Important: Most of these symptoms are caused by food proteins in breast milk, not the milk itself. Always see a doctor for proper evaluation.
What to Do
- If a true human milk allergy is confirmed, stop breastfeeding or giving expressed milk.
- Babies may need special hypoallergenic formula.
- Always work with a pediatrician, allergist, or nutrition specialist before changing feeds.
Common Causes
Most allergic reactions in breastfed babies come from what the mother eats:
- Cow’s milk protein – most common
- Soy
- Eggs, wheat, nuts, fish – less common
The mother’s body breaks food down into small pieces. These tiny proteins can sometimes trigger an allergic reaction in babies.
Where to Get Help
- Pediatrician / Pediatric Allergist: First for evaluation and diagnosis
- Lactation Consultant (IBCLC): Guidance on diet changes and safe feeding
- Food Allergy Research & Education (FARE): www.foodallergy.org
- La Leche League International: www.llli.org – Support for breastfeeding moms
Key Takeaway
- True human milk allergy is extremely rare.
- Most reactions come from foods passed into breast milk.
- Only confirmed cases should stop breastfeeding, with a doctor’s guidance.