Milk Allergy

How common is milk allergy?

Milk allergy is one of the most common food allergies in childhood affecting about 1-2% of preschool children. Milk allergy is much less common in school age children (less than 0.1%). It is often due to allergy (IgE) antibodies against milk proteins. The reactions caused by these antibodies are called immediate allergic reactions. These antibodies can be detected with an allergy test such as a skin prick test. Not all children with a positive milk allergy antibody test develop reactions on having milk or foods containing milk. If your child has a positive allergy test but has never had milk, your doctor will determine the chance of developing a reaction if there is exposure to milk, usually by doing a 'milk challenge' in hospital.

What are the symptoms of milk allergy?

The majority of immediate allergic reactions to milk are mild and consist of hives around the mouth or more generalised hives on other parts of the body. Swelling of the lips and around the eyes can also occur. Some children may develop hives from skin contact with milk. These are usually restricted to the area of skin that came into contact with the milk and do not always mean your child will develop worse symptoms from drinking milk. Your doctor will help to sort this out. A less common symptom is abdominal pain and vomiting which occurs soon after exposure to milk. More sensitive children can develop coughing, wheezing, difficulty breathing or hoarseness of the voice due to an allergic reaction occurring in the airway. In the most severe cases collapse and loss of consciousness and can occur. Milk or milk containing foods are less likely to cause severe reactions as compared to peanut. Very rarely, very sensitive individuals have died from a severe allergic reaction to milk.

Milk can also cause delayed reactions which are not due to IgE allergy antibodies. These delayed reactions can have symptoms such as worsening of eczema, diarrhoea and vomiting.

How is milk allergy diagnosed?

In most cases the clue to milk allergy is the start of symptoms soon after exposure to milk or milk containing foods (a few minutes to 1-2 hours). Another common clue is the occurrence of redness and hives soon after milk or containing foods such as ice cream or yoghurt touch the skin. The presence of allergy IgE antibodies to milk can be confirmed by an allergy skin prick test or a blood test (called a RAST test). It is important to realise that not every child with a positive allergy test will develop symptoms on exposure to milk and the interpretation of the test should be discussed with your doctor. Once a diagnosis of milk allergy has been made, you should not feed your child with milk unless this has been discussed with your doctor.

Allergy skin tests and blood tests are not helpful in diagnosing delayed reactions to milk. These delayed reactions can only be definitely diagnosed by a process of removal of milk containing foods from the diet and rechallenge if the symptoms resolve. Milk based foods should not be removed from your child's diet without the advice of your doctor and the assistance of a dietician.

What about baby formula?

The most commonly used formulae are made from cows' milk proteins and will cause reactions in cows' milk allergic children .Hypo-allergenic formulas, eg the HA formulas, are not appropriate for babies with diagnosed milk allergy. Some formulae are made from soy and do not contain milk. Soy based formulas are suitable for many infants who are allergic to cows' milk.

There are special formulae made for milk allergic children which have been treated to break down the cows' milk to non allergy producing fragments. These formulas may be prescribed by your doctor for your baby if they have milk allergy and cannot have a soy formula, and are only available on prescription from a chemist.

How do I avoid exposing my child to milk?

Milk or milk products may be found in foods we don't always expect them to be in. It is important to use common sense and read food labels carefully. The following food labels indicate the food is made from or likely to contain milk proteins. Obtain a milk free diet sheet to help you avoid milk.

• Butter
• Buttermilk
• Casein and caseinates
• Cheese
• Cheese powder
• Condensed milk
• Cottage cheese
• Cream
• Curds
• Custard
• Dairy solids
• Hydrolysates (casein, milk protein, whey)
• Evaporated milk
• Ghee, butter oil, butter fat
• Goat's and sheep's milk
• Ice cream
• Infant formula (cow's milk based)
• Lactalbumin
• Lactoglobulin
• Low fat milk
• Malted milk
• Milk
• Milk derivative
• Milk protein
• Milk solids
• Non-fat dairy solids
• Non-fat milk solids
• Nougat
• Pro-biotic drinks
• Skim milk
• Skim milk solids
• Sour cream
• Sour milk
• Whey
• Yoghurt

Is low fat or skim milk less likely to cause an allergic reaction?

No. The allergy producing part of the milk is in the protein not the fat part of the milk.

Is A2 milk a good alternative for milk allergy?

No. A2 milk contains both lactoglobulin and casein which are the most common "allergenic" parts of milk. It is not suitable for milk allergic people.

Is goat or sheep milk a good alternative?

No. There is a lot of overlap in the allergy causing parts of goat and sheep milk and cows' milk .Cows' milk allergic children are more likely to react to these milks than other cows milk substitutes that do not contain any animal milk protein. 90% of children will react to these milks if they are cows' milk allergic.

Is lactose intolerance the same as milk allergy?

No. Lactose intolerance occurs because the milk sugar called lactose cannot be completely digested in the bowel. The usual symptom is diarrhoea. A formula without any lactose (eg lactose-free infant formula) used to treat lactose intolerance can still cause milk allergy.

What about foods with a label that says "may contain traces of milk"?

Some foods may carry a warning on the label "may contain traces of milk". This usually indicates that the food is made in a facility that also makes a food containing milk. Discuss what to do about these foods with your doctor.

Can my child grow out of milk allergy?

Most infants and young children will grow out of their milk allergy. Children with the delayed reactions (not caused by IgE antibodies) are more likely to outgrow their milk allergy at an earlier age than children with milk allergy due to IgE allergy antibodies. Approximately 90% of children with delayed and 50% with immediate reactions will grow out of their allergy by 3-5 years of age. Those children who have had more severe immediate reactions with breathing problems may be less likely to outgrow their allergy than children with milder reactions. Your doctor can determine whether your child has outgrown immediate milk allergy by monitoring the allergy tests every 12 months or so.

Is my child likely to have a severe reaction from casual contact with milk product on benches, other children's hands or by smelling milk?

No. Severe reactions from casual contact are extremely rare.

Can I prevent milk allergy in my future children?

There are no steps which can guarantee a child will not develop milk allergy. There is no evidence that avoiding cow's milk in pregnancy prevents milk allergy in the baby. The evidence is unclear whether avoidance of cows milk by the mother while breastfeeding will alter the development of milk allergy in the baby.

What is an Epipen?

Epipen is an emergency device which injects a dose of adrenaline into the muscle. It is used to treat severe reactions to milk. The drug adrenaline reverses the severe allergic reaction and can be lifesaving.

Should my child carry an Epipen?

Children who have had a serious immediate reaction to milk with involvement of the airways and lungs should have an Epipen. Children do not need to have an Epipen for delayed reactions. The need for children with less serious immediate reactions and babies to have an Epipen depends on a number of factors which should be discussed with your doctor. If you have an Epipen it is very important that you understand how and when to use it and that you have a written anaphylaxis action plan provided by your doctor.

• Most children will outgrow their milk allergy by the age of 5-8 years.
• Learn to recognize the different types of food labels which indicate that the food contains cows' milk products.

Where can I find more information on the Internet?

• The CHW diet sheets available on http://kidshealth.chw.edu.au/fact-sheets/#Allergy
• The Australian Society of Clinical Immunology and Allergy (ASCIA) website contains useful information on food allergy written by Australian specialists (www.allergy.org.au).

Written by the Department of Allergy, Immunology and Infectious diseases The Children's Hospital at Westmead.