Milk allergies in children: Everything parents need to know

In his latest online article, renowned consultant paediatrician Dr Tom C Dawson explains everything parents need to understand about milk allergies in children, including the different types of milk allergies, how they are diagnosed and the dietary strategies parents can adapt.

What are the common types of milk allergies in children, their symptoms, and signs to watch for?

Two main types of food allergy in children involve two different parts of the immune system. 

The differences are defined by the timing of the reaction and the presence of an antibody present in milk IgE antibody.

There is an immediate type of allergy sometimes called IgE antibody-mediated allergy. This will usually occur rapidly, mostly within minutes but sometimes up to 2 hours later. This can cause itchiness and a redness to the skin called erythema. There can also be a wheel-like rash that looks like a nettle sting rash and also swelling which can occur anywhere but often involves the lips, around the eyes on the face or the ears. 

There may also be a flare of existing eczema. Other symptoms include vomiting, diarrhoea, abdominal pain and colic. Sometimes there can be acute rhinitis or conjunctivitis. A severe reaction including the respiratory or cardiovascular system called anaphylaxis may occur, but it is very rare.

The second type is a delayed reaction, typically occurring more than 2 hours and sometimes up to 72 hours after ingestion. This is caused by a different part of the immune system and so sometimes called a non-IgE antibody-mediated allergy.  Usually, several symptoms occur together with this type of allergy and mainly involve the gastrointestinal system or the skin. 

These babies are typically irritable or suffer from colic and have vomiting and reflux, food refusal or aversion. They appear to experience abdominal discomfort with the painful passing of gas. The stools are loose and more frequent. Sometimes blood and mucous can appear in the stools and this may be the only sign. Constipation with excessive straining and passage of soft stools can also be typical. The skin may have moderate eczema. Sometimes there is flushing and redness (erythema) to the skin as well as itch.

There is some overlap of these symptoms in babies which can be hard to differentiate.

How are milk allergies diagnosed in children, and what tests are typically used to confirm specific allergens?

Diagnosis is usually made by taking a careful description of the symptoms from parents and where there is doubt or a confirmation of IgE antibody-mediated allergy is required, an IgE test can be done. 

This can either involve a blood test for the IgE to milk or a skin prick test for the antibody in the skin. This is where a drop of milk is placed on the skin and a prick through the top surface of the skin is made forming a tiny well in the skin. The excess is wiped away and 10 -15 minutes later the test is read.  A positive test will look like a nettle sting or bite. This will fade over the next 20-30 minute

What are the potential complications and risks associated with children's food allergies?

Having one food allergy does increase the risk of further food allergies developing. Having either form of food allergy increases the risk so having a non-IgE antibody reaction to milk will increase the risk of other allergies like egg or peanut allergy. These children are more likely to already have significant eczema.

Anaphylaxis (serious reaction) is rare in the young age group but does increase with age peaking in adolescence. Parents must be aware of which foods they should avoid. They, and all carers for the child should carry an allergy action plan and be aware of how to instigate this in the case of an accidental exposure to milk. This may include an antihistamine liquid and sometimes an adrenaline auto-injector

Most children have eczema (atopic dermatitis) and it is thought that the exposure through the damaged skin barrier instead of the gastrointestinal tract contributes to the development of food allergy. Therefore, careful management of the eczema is important to reduce the opportunities for this happening.

How can parents recognize and effectively manage these risks?

Most reactions occur outside the home in restaurants, at parties or their grandparents' houses. It is important that carers are told to check ingredients and look for MILK in the ingredients list.  Most children do not need to avoid foods which “may contain” milk although this should be advised by their allergist. Strategies should be in place in the nursery to avoid food sharing and accidental exposure. Although some children will react on skin contact, this should not cause a serious reaction unless the milk is ingested. Surfaces should be cleaned at home to avoid cross-contamination and using the butter knife for the plant-based spread for example would be likely to trigger a reaction.

Because of the risk of other allergies developing, it is important that other foods are introduced early (from 4 months of age) ideally when the mother is still breastfeeding. Around 10% of children with milk allergy will also have soya allergy. 

Several foods are recommended to be introduced early as there is evidence now that this is likely to prevent an allergy from developing later and severe reactions in this age group are very rare. These would include egg, soya (you could use a soya yoghurt), nut butters (including peanut, hazelnut and cashew nut) or ground nuts mixed in with a tolerated food, fish, wheat and sesame (humus or tahini). This should be under the direction of a dietitian or allergist.

What dietary strategies can parents employ to ensure proper nutrition while avoiding allergenic foods, and when should they consider consulting a dietitian or nutritionist for guidance?

Breastfeeding should continue where desired and most mothers do not need to cut milk from their own diet unless it is very clear that their child is reacting. Very little milk protein is present in the breast milk and this may be a way to accelerate outgrowing of milk allergy. If mothers are eating a milk-free diet while breastfeeding feeding, they should also seek support and have calcium and vitamin D supplements as their calcium stores will be depleted for the breast milk.

Calcium and vitamin D are the nutrients that can be difficult to obtain if you suffer from a milk allergy. These are available in beans, best of both breads and fish but dietetic support is always recommended.

When children are older than one there are options for reintroduction of milk via a milk ladder for those children with a non-IgE mediated allergy. This should be advised by a dietitian or an allergist. For those with IgE-mediated allergy, there is the possibility of helping them outgrow this faster by using something called specific oral tolerance induction (SOTI). This should be advised by their allergist and involves careful graded exposure to milk.

What is the role of milk in a child's development, and how does it contribute to their overall nutrition and growth?

Most children will learn to live with their allergy and be competent in asking before eating foods. They will learn their management plan and know to ask for help with a reaction. They will become used to carrying treatment for potential reactions around with them. There are risks of developing excessive anxiety around foods in some children and this can be treated with psychological input.

A small number of children with non-IgE antibody-mediated milk allergy will find that they cannot tolerate large amounts of milk in their diet and that above a threshold they will get gastrointestinal symptoms.

There is no evidence to suggest development or growth is affected by either type of milk allergy. Untreated milk allergy can result in faltering growth early on.

What are the potential long-term effects or complications of milk allergies on a child's development?

Most children will outgrow these allergies but the risk of not doing so does increase with the more allergies a child has. Most children with non-IgE antibody-mediated milk allergy will outgrow this by the age of three years. For the IgE-mediated milk allergy, this may be later at around 8 years.  There is no difference demonstrated in the growth or development of children treated with alternative diets for milk allergy.

There is no evidence of the consequences of long-term non-adherence to a dairy-free diet in those with non-IgE antibody-mediated allergy like there is for other illnesses such as coeliac disease.

How can these be managed or prevented?

It is important to intervene early with diagnosis and management. Early managed reintroduction may allow milk to be tolerated in the diet earlier than if not. No preventative measures are currently available.

Dr Tom C Dawson is a leading consultant paediatrician based in Birmingham & Worcester. If you would like to book a consultation with Dr Tom C Dawson, you can do so today via his Top Doctors profile.