What is CMA?

Cow’s milk allergy or ‘CMA’ (sometimes referred to as cow’s milk protein allergy or ‘CMPA’) is an allergic reaction to the proteins in cow’s milk. It is one of the most common food allergies in children under 5 years, affecting 2-7.5% of babies.1

The symptoms of CMA result from the body’s immune system detecting cow’s milk proteins as potentially harmful, which leads to an immune system response. This response results in the common digestive, respiratory and skin reactions associated with CMA.2

The type of CMA a baby has depends on how the immune system responds to the cow’s milk protein.1 Your baby can also have a mix of both types of CMA and can therefore show both immediate and delayed symptoms.2,3

What are the symptoms of CMA?

IgE-mediated or 'immediate' CMA

Some babies’ immune systems react immediately after ingesting cow's milk proteins through antibodies called IgE, with symptoms appearing within minutes1,2

Non-IgE-mediated or 'delayed' CMA

Other babies’ immune systems have a different and much slower reaction to cow's milk protein, with symptoms appearing hours or even days after ingesting cow’s milk1,2

CMA has a variety of symptoms, many of which can be similar to the expected behaviour of a baby. Symptoms include:4

graphic of symptoms - Desktopgraphic of symptoms - Desktop

Does my baby have CMA?

The common nature of these symptoms (e.g. diarrhoea or a rash) may mean that some parents are reluctant to speak to their healthcare professional at first.

However, the process for diagnosing CMA can take a long time for many parents, with research showing that it takes an average of 10 weeks and 4 visits to a healthcare professional from the first sign of symptoms.5

Being able to spot the signs of CMA yourself may help speed up this process — if your baby is showing one or more of the symptoms in the checklist below*, you may wish to set up an appointment with your baby’s GP to discuss further.


Immediate symptoms


  • tickItching or tingling feeling around the lips or mouth
  • tickEczema
  • tickErythema
  • tickHives
  • tickSwelling—typically the lips, face and around the eyes


  • tickVomiting
  • tickAbdominal cramps or discomfort
  • tickDiarrhoea
  • tickSwelling of the lips, tongue or palate
  • tickItchy mouth


  • tickCoughing, chest tightness, wheezing or shortness of breath
  • tickNasal itching, sneezing, runny nose or congestion (with or without conjunctivitis)


  • tickRarely, much more serious symptoms can develop; especially breathing difficulties—this is called anaphylaxis
  • tickOther systemic allergic reactions

Delayed symptoms


  • tickItching or tingling feeling around the lips or mouth
  • tickEczema
  • tickErythema or flushing


  • tickGastro-oesophageal reflux disease (GORD), vomiting
  • tickColic/irritability
  • tickAbdominal pain/discomfort
  • tickLoose and/or frequent stools
  • tickA little blood or slime in the stools
  • tickFood refusal
  • tickConstipation (especially straining to pass a soft stool)
  • tickPerianal redness
  • tickPale appearance/tiredness
  • tickFaltering growth with at least one gastrointestinal symptom


  • tickCoughing, chest tightness, wheezing or shortness of breath

Adapted from NICE.2

*This is not an exhaustive list of CMA symptoms. The absence of these symptoms does not exclude a diagnosis of food allergy.

Find out what you need to know when preparing to visit your GP

CMA: cow’s milk allergy. GP: general practitioner; IgE: immunoglobulin E.


UK-SIMILAC-2000018 November 2020