How do I know if it's cow’s milk allergy or colic?

green ribbon cmaAll babies cry, but some cry louder and longer than others – even when they’re not hungry, tired, or in need of a nappy change. This excessive, unexplained crying could be due to colic or a sign that a baby has an allergic reaction to cow’s milk protein. (You should also be aware that colic is itself one of the signs of cow’s milk allergy.) Find out in this section what the difference is between cow’s milk allergy and colic, so you have a better idea of what might be causing your baby’s crying.


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What is colic?

Colic is the medical term used to describe excessive, frequent crying in babies who otherwise appear to be healthy and well. The crying is usually very intense, and the baby’s face might be red and flushed and they may clench their fists, draw up their knees or arch their back. The crying tends to happen for at least 3 hours a day, for more than 3 days a week, and lasting for 3 weeks or more.

Alongside the crying, other signs of colic in a baby could include:

  • Pulling the legs up to the tummy
  • Arching the back
  • Stiffening the limbs
  • Being full of wind
  • Having a tense, bloated belly

When does colic occur and how common is it?

It usually begins within the first few weeks of life but often stops by the time the baby is 4 months old, and by 6 months at the latest.

Colic is relatively common – it’s thought to affect around 1 in 5 babies.

What causes colic?

Experts aren’t really sure what causes colic or why certain babies get it but not others. Food allergies like cow’s milk allergy (the most common type of food allergy in infants and young children) are one possible cause. Babies with cow’s milk allergy are likely to show colicky symptoms. There are various other ideas about what lies behind colic:

  • Some researchers think that indigestion or wind may play a significant role
  • Other researchers believe that babies with colic may, for a few weeks while their gut is maturing, be sensitive to certain substances that are found in breast or formula milk
  • Another theory suggests that some babies may be more emotionally sensitive than others, and have problems "turning off" their crying response
  • It is believed that women who smoke during pregnancy could double their chances of having a baby who develops colic

Does my colicky baby have CMA?

If you think that your colicky baby might have cow’s milk allergy, make an appointment to see your doctor and discuss your concerns.

If your baby has cow’s milk allergy, they might show other symptoms besides colic such as eczema, vomiting and diarrhoea. Take a look at the symptoms page for more information on what signs of cow’s milk allergy to look out for.

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To find out if cow’s milk allergy is causing your baby’s colic and other symptoms, your doctor may carry out some allergy tests including advice to put your baby on an elimination diet followed by a food challenge.

What can I do if my baby has colic?

Having a baby who’s in tears all the time can be exhausting, and often worrying as a parent. But it’s important to remember that colic doesn’t mean you’re doing something wrong or that your baby’s rejecting you. Speak to your doctor, who can find out if there’s an underlying reason causing the colic. Your doctor can also provide advice on how to soothe your little one. Every baby reacts differently, so you might find that some things work better than others. Here are a few suggestions to try:

  • Hold your baby in different positions – try carrying your baby in an infant sling or front carrier on your chest as you walk around, as the body contact and motion can be calming. To ease any wind, try laying your baby tummy-down across your knees while gently rubbing their back
  • Play calming sounds – recreate the soothing womb environment with soft music, a fan, or a sound recording of a heartbeat
  • Use gentle, rhythmic motions – steady movements are soothing. Cradle your baby while rocking in a chair, or try a vibrating infant seat
  • Massage your baby’s skin – babies love skin-to-skin contact, and you might find that regularly massaging your baby makes them less irritable and reduces their crying. Ask your healthcare professional for more information on infant massage
  • Hypoallergenic formula – if your baby is bottle-fed, your doctor may recommend an extensively hydrolysed formula designed for babies with cow’s milk allergy to reduce colic symptoms. In this type of formula, cow’s milk proteins have been broken down allowing your baby to digest the milk proteins more easily. Guidelines for managing colic recommend the use of an extensively hydrolysed formula

Speak to your doctor about possible food allergies that may be causing your baby’s colic, and whether you should try eliminating potential allergy-causing foods that contain cow’s milk protein. You should only make changes to your baby’s diet under the supervision of your doctor or a specialist.

Which foods contain cow’s milk protein?

And remember to give yourself a break! Looking after a baby with colic can be exhausting so it’s important that you look after your own wellbeing too, so don’t be afraid to ask for help from family members or friends when you start to feel overwhelmed.

As well as colic, cow’s milk allergy is sometimes confused with lactose intolerance. Find out the difference between cow's milk allergy and lactose intolerance.

You can find out more about colic from NHS Choices.