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Part of the London Allergy Clinic
Diagnosis & Specialist Care of Allergy & Clinical Immunology - Since 1982
Cow's milk protein allergy — often shortened to CMPA — is one of the most common food allergies in early childhood. It happens when a baby's immune system reacts to the proteins found in cow's milk. It is different to lactose intolerance (usually a deficiency of the lactase enzyme), which is a separate and unrelated issue.
CMPA can affect babies who are formula-fed, and also exclusively breastfed babies, who can react to tiny traces of milk protein passed through their mother's breast milk. Estimates of how common CMPA is vary depending on how it's measured, but UK research places it among the most frequent food allergies in infancy — with one major European study finding the UK had the highest confirmed CMPA rate of all the nine countries studied, at just over 1% of children by age two.
The wider range cited across UK clinical guidance is broader still, generally somewhere between 2% and 7% of babies in their first year, reflecting how differently CMPA can present from one baby to the next.
The reassuring news is that the great majority of children outgrow CMPA, often by the age of three to five.
Why Diagnosis Can Be Tricky
CMPA doesn't always look the way people expect. There are two broad types:
IgE-mediated CMPA — symptoms appear quickly, usually within minutes to two hours of milk exposure. These can include hives, swelling, vomiting, or in rare cases, a more serious reaction. This type can usually be identified through skin prick or blood testing.
Non-IgE-mediated CMPA (also known as a delayed allergy) - symptoms can appear anywhere from two hours to a few days after exposure. These are more varied and can include reflux, colic-like symptoms, eczema, constipation, loose stools, or poor weight gain. It cannot be identified through skin prick or blood testing, but instead through controlled elimination & reintroduction under guidance.
Because these symptoms overlap with so many other common baby issues, non-IgE CMPA is often missed, misattributed, or only identified after a process of careful elimination.
This is exactly why a specialist assessment can make such a difference — particularly for non-IgE presentations, where standard allergy tests often aren't useful and a detailed clinical history matters far more.
What We Assess
• A detailed history of your baby's symptoms, feeding pattern and timing
• Whether symptoms point towards an IgE or non-IgE presentation
• Growth and weight gain
• Family history of allergic conditions
• Appropriate testing, where relevant (skin prick or specific IgE blood testing for suspected IgE-mediated CMPA)
• A clear, structured management and feeding plan - including explanation of the milk ladder
About Our Approach
Both Dr Tammy Rothenberg and Dr Emily Derrick regularly assess and manage CMPA in babies and young children, working alongside our specialist Paediatric Allergy Dietitian, Misbah Primett, to provide complete dietary and nutritional support alongside the clinical diagnosis.
A clear diagnosis matters — both to avoid the discomfort and worry of ongoing, unexplained symptoms, and to avoid unnecessary dietary restriction where it isn't actually needed.
What Management May Involve:
• Guidance on appropriate hypoallergenic formula, where needed
• Maternal dietary guidance for breastfeeding mothers
• A structured plan for reintroducing milk when the time is right, often using a 'milk ladder' approach
• Nutritional support to ensure normal growth and development throughout
• Ongoing review as your baby grows, since most children do go on to outgrow CMPA
If you suspect your baby may have CMPA, or you've had an unclear or unconfirmed diagnosis and would value specialist clarity, we're here to help.
Call us, email us or WhatsApp us — a real person will always respond, six days a week.
📞 0207 637 9711
✉ enquiries@londonallergyclinic.com
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