Milk Allergies

Lactose intolerance and cow’s milk protein allergy – what are they?

Is my baby lactose intolerant or do they have a cow’s milk protein allergy?

Many new mums with a newborn have suspected that their little one may have a milk allergy or intolerance. However, it can be difficult to tell the difference between a cow’s milk protein allergy (CMPA) and lactose intolerance as many of the signs and symptoms are similar.

What is the difference between an intolerance and an allergy?

It is important to note that an allergy is NOT an intolerance. The main difference is that CMPA is a food allergy caused by a reaction to the protein in cows’ milk. Lactose intolerance is a food intolerance caused by an inability to digest milk sugar (lactose).

What is CMPA?

CMPA is the most common food allergy among babies and occurs when the baby has an allergic reaction to the protein found in milk. Some babies are a higher risk of developing a food allergy, especially if there is a family history of allergy.

What is lactose intolerance?

Lactose intolerance can be either primary or secondary. Primary intolerance is an inherited condition but it is very rare before 2-3 years of age. Secondary intolerance normally develops after your baby has been unwell, particularly following a dose of diarrhoea or gastroenteritis. This type of intolerance is usually only temporary, and lactose levels generally return to normal after 6-8 weeks.

Here is a list of some of the typical symptoms associated with lactose intolerance and with CMPA, these symptoms can be either immediate or delayed:


  • Swollen face, lips or tongue • Diarrhoea
  • Hive, rash, redness or itching • Gas
  • Eczema
  • Diarrhoea
  • Vomiting
  • Breathing difficulty
  • Reflux
  • Constipation
  • Blood or mucous in stool

Lactose intolerance

  • Diarrhoea
  •  Gas
  • Bloating
  • Cramping

What do I do if my baby has been diagnosed with CMPA?

  • Treatment should only begin following the diagnosis of CMPA from a healthcare professional.
  • If your baby has been diagnosed with CMPA, breastfeeding is the best source of nutrition.
  • If you are breastfeeding and your baby is showing some signs and symptoms of CMPA this does not mean that they are allergic to breast milk, although some very sensitive babies can have allergic reactions to breast milk. In this instance, experts may recommend the elimination of milk and dairy products from your own diet. This should only be done with the guidance of your healthcare professional so speak to a doctor or public health nurse if you’re concerned.
  • If your baby’s symptoms are still there even when you are avoiding dairy products in your diet, your healthcare professional may advise switching to a specialised formula.
  • Bottle-fed babies are also usually recommended to move on to a special formula for CMPA.

The good news is that many babies and toddlers will outgrow their allergy as they get older. After CMPA has been diagnosed and treated it is important to ask your healthcare professional when your baby or toddler will be reassessed.

If you’ve got a question about cow’s milk protein allergy or lactose intolerance and you’d like to talk to someone about it, do contact our Careline at 1800 570 570 or always speak to your doctor, midwife or public health nurse if you are concerned.