Food Allergy

What causes food allergies?

Allergies are the result of incorrect decisions by the immune system. In infancy, the immature immune system must quickly learn what is safe and what is not, and sometimes it gets it wrong.

Many changes in our modern diet, lifestyle and environment are likely to be causing the current allergy epidemic.

What are the symptoms of an allergic reaction?

Food allergic reactions range from mild rashes to life threatening reactions. The typical allergy rash is caused by histamine release and appears as raised pale welts surrounded by redness - sometimes referred to as hives.

Swelling can also affect the throat making breathing difficult. A massive histamine release during anaphylaxis can cause a dangerous drop in blood pressure, with patients even losing consciousness.

What are the most common food allergies?

Although any food can potentially cause an allergic reaction, more than 90 per cent of childhood food allergies in Australia are to common foods such as hen's eggs, cow's milk, soy, peanuts, tree nuts, wheat, fish and shellfish. In general, allergies to egg, milk, soy and wheat are transient and children will usually grow out of them. However allergies to peanuts, tree nuts, fish and shellfish tend to be life-long.

Recommendations for reducing the risk of food allergy

• When pregnant and breastfeeding, still eat all common allergy-causing foods, unless you have an existing allergy to a food.
• When your infant is ready, at around 6 months, but not before 4 months, start to introduce a variety of solid foods, starting with iron rich foods, while continuing breastfeeding.
• All infants should be given allergenic solid foods including peanut butter, cooked egg, dairy and wheat products in the first year of life. This includes infants at high risk of allergy.
• Hydrolysed (partially and extensively) infant formula are not recommended for prevention of allergic disease.

To reduce the risk of your baby developing a food allergy, it's no longer recommended that you avoid or delay introducing common allergy-causing foods - such as eggs and peanuts.

If worried about giving a food for the first time, introduce it gradually by rubbing a small amount inside the lip and waiting 10 minutes. Signs of an allergic reaction include rash, hives, swelling of lips and eyes. If difficulty breathing (also hoarse voice and cough) occurs, lay the child down and call an ambulance.

*If you have concerns that your child has a food allergy, please seek medical advice.

More information

• Australasian Society for Clinical Immunology and Allergy
• The Allergy Epidemic: A Mystery of Modern Life - Dr Susan Prescott