(From Allergy Today Issue 122 Spring 2007. To read the rest of the article, subscribe to Allergy Today here.)

Milk allergy is the most common allergy in infants and very young children, and it can be difficult to diagnose. Because milk is also one of the mainstays of the everyday Kiwi kid’s diet — cheese, yoghurt, baked goods, chocolate and lollies —there’s a big gap to fill when you have to avoid it. Inga Stünzner reports.

Public enemy number one

When Thomas Aish was only three months old, he started showing signs of eczema, with his skin drying out and turning red in the creases of his elbows and knees. It worsened when he started on solids, so by the time he was eight months old, he had a stubborn patch of eczema on his cheek and an infection in the crease of his ear that wouldn’t budge, no matter how many creams his mother Lisa used.

“I had my suspicions,” says Lisa, whose eldest son, six-year-old Anton, is severely allergic to peanuts, nuts and eggs. “I gave Thomas some toddler yoghurt as soon as he turned one, and this tests confirmed it. He immediately became itchy and flared up around the mouth.”

Thomas was bundled off to the family’s allergy specialist, and both a skin prick test and a RAST (blood) test confirmed a milk allergy, with the added bonus of dust mite allergy.
“After having a child that is at risk of anaphylaxis to three foods, it was a relief to find out that Thomas has only one food allergy,” Lisa says.

Although perhaps of little comfort, Lisa was far from alone in dealing with a milk allergic infant. In Australia and New Zealand one in 50 babies are allergic to cow’s milk (dairy)

Immediate and not so immediate

Cow’s milk allergy can be very difficult to diagnose because symptoms are so varied. This is due to there being two types of milk allergy: IgE-mediated (immediate response) and non-IgE mediated (delayed response).

So what does this mean?

Someone with an IgE-mediated allergy will usually have an immediate response to an allergen, which occurs when the immune system responds to milk protein as being an enemy and develops allergic antibodies (called IgE) to it. The IgE binds with the milk protein and causes cells to release chemicals that result in symptoms such as hives, swelling of the face, tongue or other parts of the body, vomiting, diarrhoea, noisy breathing or wheeze or eczema. Severe reactions involving the breathing and/or cardiovascular system are called anaphylaxis, which can also result in low blood pressure (shock) and cause babies to be pale and floppy or older children to collapse. This type of milk allergy is often referred to as being an immediate response.

Non-IgE mediated cow’s milk allergy (often referred to as delayed) still involves the immune system, but it does not involve IgE antibodies. It can occur several hours after moderate amounts of cow’s milk have been consumed, and symptoms can include vomiting and diarrhoea and sometimes blotchy rashes or worsening eczema.

Reactions can even occur a day or up to several days after having normal amounts of cow’s milk and symptoms can include eczema, vomiting, diarrhoea or asthma. This type of response is often referred to as a delayed response.

“Milk is one of the most likely allergens at the beginning of life,” explains Professor Christophe Dupont, from the Hospital Cochin Saint Vincent de Paul in Paris, France.