Even breastfed babies can have mild reactions if the mother eats a food the baby is allergic too - the substance in the food causing the allergy can be passed on in breastmilk. More than 80 per cent of food allergy reactions are due to egg, peanut, cow's milk and nuts. But most food reactions are caused by another problem called food intolerance. This can be confusing because food intolerance and food allergy can cause similar symptoms - the difference is that the reactions tend to take longer to appear, and don't always happen each time the food is eaten. Symptoms of food intolerance are recurrent hives, abdominal pain, bowel problems, mouth ulcers, headaches and irritable behaviour.
Children can be hyperactive, moody and restless with lots of tantrums over minor problems.
The reason children develop food allergy isn't really understood - but we do know the problem is becoming more common, especially in industrialised countries. Peanut and sesame seed allergies are now more common because more people are eating these foods. Breastfeeding doesn't help prevent food allergies as the food substances causing the problem are passed on in the milk. It's not possible to have a food allergy unless you're exposed to the food causing the allergy. Babies who develop eczema or asthma in the first 12 months of life are the mostly likely to have food allergy.