Over-Diagnosis and Under-Diagnosis are common.

What is Cow’s milk allergy, and what are the symptoms?

Cow’s milk allergy affects around 1 in 20 babies under 1 year of age.

Cow’s milk allergy is an immune reaction to proteins in milk. Normal formula milk is based on cow’s milk. However, the allergy can also occur in breast-fed babies when the mother drinks cows’s milk.

There are two types of cow’s milk allergy

The IgE mediated (IgEm) cows milk allergy causes a more dramatic presentation than The non-IgE cow’s milk allergy.

IgE type of cows milk allergy

The other name for IgE allergy is ‘immediate hypersensitivy’. Symptoms occur within minutes of having cows milk, and may include:

  • Hives-type rash with itchy red skin
  • Swelling of the face or lips
  • Tummy pains
  • Vomiting and/or Diarrhoea).
  • Wheeze or hayfever type symptoms.

It is usually fairly obvious that these symptoms are caused by cow’s milk.

Non-IgEm type of cows milk allergy

Symptoms occur later after exposure than the IgE type of allergy. Indeed, the other name for Non-IgE allergy is ‘delayed hypersensitivity.’

It may therefore not be obvious that milk is causing the symptoms. The delayed type is much harder to diagnose than the immediate type because the symptoms do not immediately correlate with the last feed. This type of cow’s milk allergy may be missed.

Symptoms may include:

  • Vomiting up milk
  • Loose bowel motions
  • Colic
  • Constipation (occasionally)
  • Perianal redness.

Gastrointestinal symptoms are much more common than skin symptoms but it is also possible to experience Eczema, red skin, and itching. How can you tell whether a baby with eczema has cow’s milk allergy? Severe eczema starting at a young age is more likely to be caused by cow’s milk allergy.

What Tests are there for cow’s milk allergy?

There is an allergy test only for the immediate IgE type of allergy. About half of those who test positive for the cow’s milk allergy actually have symptoms caused by the cows milk allergy.

There is no laboratory test for delayed cow’s milk allergy. The only way to ‘know’ is by eliminating all cow’s milk for 4 weeks. Your doctor can advise you how to safely go about this.

Which speciality formula should I use?

It’s best to go to the manufacturer’s website for their latest products. Aptamil provide a good range of products. For mild to moderate cow’s milk intolerance, your doctor might advise you to try AllerPro1 (age under 6 months) or AllerPro2 (age over 6 months). The immediate type of allergy is generally harder to treat and your GP will probably refer you to an allergy specialist or consider the use of Aptamil Gold Pepti Junior (age 0-6 months). You can buy these from a pharmacy without prescription. It should be emphasized that you need to discuss the plan fully with your GP.

What is the role for soya milk?

Soya milk should not be used under 6 months of age because Soya contains a small amounts of isoflavins that have a weak hormonal effect. There is also some cross-reaction between soya proteins and cow’s milk proteins.

How quickly should symptoms improve on the exclusion diet?

Most symptoms will usually resolve within 4 weeks of a cow’s milk elimination diet.

How long should the exclusion continue, and when do children outgrow the allergy?

This depends on the type of allergy. The delayed type usually sorts itself out by 2 and a half years of age (by then, most are cow’s milk tolerant). A challenge can be done every 6 months from the age of 1 year. Milk may be re-introduced with 5ml of cow’s milk that is doubled each day until a normal serve is achieved.

The immediate type lasts longer with just over half outgrowing their milk allergy by age 5. Tolerance is assessed using allergy tests.

Should I see a dietician?

There is some evidence that some babies and infants on the exclusion are more likely to be malnourished or obese. Your GP may advise that you see a dietician.

1: Agostoni C etal; east-feeding: a commentary by the ESPGHAN committee on nutrition. J PediatrGastroenterol Nutr 2009;49:112-25

WRITTEN BY: Richard Beatty