Could my child have a food allergy?

Food allergies occur in about one in 20 kids, according to the Australasian Society of Clinical Immunology and Allergy (ASCIA), but in adults this number has dropped to about one in 100.

“The majority of food allergies in children are not severe, and will disappear with time,” ASCIA says, although it does stress that some can be severe causing life-threatening reactions known as anaphylaxis .

How do you recognise a food allergy?

ASCIA admits that the term ‘allergy’ is often misused to describe any adverse reactions to food. There are some fairly immediate reactions – within the first 30 minutes – which could point to an allergy including:

• hives (urticaria)
• swelling around the mouth
• vomiting
• Other symptoms are:
• runny or blocked nose
• stomach pains
• diarrhoea (chronic or more acute)
• eczema
• infantile colic
• failure to thrive in infants

Food intolerances are not allergic reactions and cause a completely different bodily response. Even though the symptoms can be similar (e.g. diarrhoea, vomiting) food intolerance is a ‘chemical’ reaction that some people have after eating or drinking some foods; it is not an immune response. An intolerance is a lot more common than an allergy.

What is an allergy?

Here’s how ASCIA describes allergies: “Underneath the lining of the skin, gut, lungs, nose and eyes are ‘mast’ cells. These are designed to kill worms and parasites.

“Mast cells are like bean bags filled with irritant chemicals including histamine and are armed with proteins called IgE antibodies (often referred to as allergy antibodies), which act to detect allergens in the local environment.”

A person allergic to peanut, for example, will have IgE antibodies capable of recognising the shape of peanut protein (the allergen), in much the same way that a lock recognizes the shape of a key. When this happens, mast cells are triggered to dump their contents (including histamine) into the tissues, causing an allergic reaction. Food allergies can develop at any time but often show up in a child before the age of five years.

The most common foods which bring on allergies are eggs, cow’s milk, peanuts and tree nuts . Less common triggers include seafood, sesame, soy and wheat.

Are food allergies increasing?

Most childcare centres, preschools and schools are now ‘nut-free’ zones. Many parents would have held birthday parties and had kids attend who couldn’t eat eggs, dairy or nuts. It seems every class has a child with a dangerous allergy.

According to ASCIA, the reasons for the increasing incidence of food allergies in kids is unclear but it suggests these possible explanations:

• the ‘hygiene hypothesis’ which proposes that less exposure to infections in early childhood is associated with an increased risk of allergy
• delayed introduction of allergenic foods such as egg, peanut or tree nuts
• methods of food processing (e.g. roasted versus boiled peanuts)
• development of allergy to food by skin exposure (e.g. nut oil-based moisturisers)

What to do if you suspect a food allergy

If your child appears to have an allergic reaction or you’re worried your child may have an allergy, ASCIA recommends you start with a visit to your GP who will ask a series of questions in a bid to narrow down what may have caused that reaction.

Skin prick allergy tests or blood tests for allergen specific IgE (commonly referred to as RAST) may be advised to help confirm or exclude potential triggers. Sometimes a temporary elimination diet under close medical and dietetic supervision will be needed, followed by challenges to identify the cause.

The ASCIA does not recommend what it calls “unorthodox” tests for food allergy including cytotoxic food testing, Vega testing, kinesiology, allergy elimination techniques, iridology, pulse testing, Alcat testing, Rinkel’s intradermal skin testing, reflexology, hair analysis and IgG food antibody testing.

“These have no scientific basis, are unreliable and have no useful role in the assessment of allergy,” it says.

How can I find out if my child has a food allergy?

To confirm a food allergy or intolerance, you need to consult an allergy specialist who will do a series of allergy tests – skin prick and blood – and who may ask your child to participate in an elimination diet for a couple of weeks before reintroducing the suspect food to confirm a food allergy.

Can I prevent my baby from developing a food allergy?

Yes, or no, depending on who you talk to. In the past, it’s been suggested that delaying the introduction of certain foods to children who seem likely candidates for food allergies may help them long-term to avoid developing an allergy. However, there is conflicting evidence as to whether this is the best course of action.

Experts do agree, though, that breastfeeding offers some protection against allergies, so breastfeeding for as long as you can, will help your child to better deal with any potential allergy problems.

Another strategy is to introduce solid food to your baby slowly. Feed her one new food at a time with several days between the introductions of new items. By being methodical, you’ll quickly be able to tell which food is causing the problem if she does have a reaction.

This article contains general information only and is not intended to replace advice from a qualified health professional.