Cows' milk allergy (CMA) occurs when your baby’s immune system reacts to the protein in cows' milk. Babies that have CMA usually have symptoms during the first few months of life. They generally grow out of it before the age of 3 years.
CMA is a common childhood allergy, affecting 2–3% of children (eg, up to 3 in every 100 children) before the age of 3 years. Babies who have close whānau members (parent, brother or sister) with allergic conditions such as eczema and asthma are more likely to have CMA.
There are 2 main types of CMA:
- IgE-mediated CMA – symptoms appear within minutes or up to 2 hours after having cows' milk protein.
- Non-IgE-mediated CMA – symptoms usually appear after 2 hours up to a few days after having cows' milk protein.
Some babies may have symptoms of both IgE-mediated and non-IgE-mediated allergy (referred to as mixed allergic reaction).
Read more about cows' milk allergy.