Does your baby have undiagnosed cows' milk allergy?

This week is food allergy awareness week and we have enlisted the help of Joan Gavin, State Registered Paediatric Dietitian within the NHS and holder of a Masters degree in Applied Paediatric Nutrition to advise on the topic of cows' milk allergy in babies. Food fad, or fact? Read on to learn more. 

  • Reflux (frequent regurgitation of feeds)
  • Constipation or loose and frequent stools
  • Eczema
  • Abdominal pain
  • Severe colic
  • Difficulty putting on weight?

If your baby suffers from any combination of the above symptoms it may be because they have an undiagnosed cows’ milk allergy. 

Surprisingly, cows milk allergy can be evident even in exclusively breastfed babies who have never consumed any cows’ milk! Cows milk allergy is one of the most common food allergies in childhood affecting more than 1 in 50 children under the age of 3 years, presenting initially in the first year of life. Babies with a mother, father or sibling with asthma, eczema or hay fever are more likely to develop cows milk allergy than those with no family history of these medical conditions.

The difference between cow’s milk allergy and lactose intolerance
Cows’ milk allergy is an immune reaction to one or more of the proteins found in milk, and is triggered either through cows milk protein present in breast milk, a formula feed or a dairy weaning food. The symptoms are easily confused with lactose intolerance, an enzyme deficiency that creates an inability to digest the milk sugar (lactose) causing similar gut symptoms, but these are not related to the immune system unlike an allergy, and require a different dietary treatment. Lactose intolerance is rarely seen in babies under 1 year except following a bout of gastroenteritis which may cause a temporary lactose intolerance.

Cows’ milk allergy can present in two ways:
a)   “immediate onset” reaction, where symptoms such as hives (nettle rash), vomiting, lip swelling, worsening of the eczema, red flushing of the face and body and breathing difficulties rapidly appear after taking a small quantity of cows’ milk

b)    “delayed onset” reaction where symptoms such as diarrhoea, constipation, reflux, blood in stools, progressive worsening of eczema appear several hours or even days after ingestion of a larger quantity of cow’s milk

“Immediate onset” reactions can be confirmed by IgE mediated allergy skin prick testing or a specific IgE antibody blood tests undertaken at an NHS hospital through GP referral to a consultant paediatrician.

“Delayed onset” reactions are the most common presentation of cows’ milk allergy and the only way of diagnosing this type of reaction is to exclude cows milk from the formula and diet, or from the maternal diet, if breastfeeding, and reintroduce it after a prescribed period of time.

Elimination of milk and dairy from the diet should always be done under the guidance of a paediatric dietitian who will take a detailed clinical history to assess, diagnose and treat the cow’s milk allergy ensuring both mother and baby are being provided with all the nutrition they need in the absence of this major food group from the diet. This is especially important in the first year of life when a baby’s nutritional requirements are high and growth is rapid.  To access a paediatric dietitian, ask your GP to refer your baby to the dietetic department at your local NHS hospital. Alternatively, for direct access to a private consultation with a paediatric dietitian email

About Joan Gavin
Joan Gavin has 20 years of clinical experience as a State Registered Paediatric Dietitian within the NHS and holds a Masters degree in Applied Paediatric Nutrition. Her specialities include food allergies and gastroenterology and she has published articles in medical journals and books. Joan can assess, diagnose and treat nutrition related conditions providing up to date practical advice suited to your child’s needs. She is a member of the British Dietetic Association and registered with the Health Professions Council.