About one in 20 babies will have a food allergy and most of these will develop in the first six to 12 months of life. If the baby is breastfed, the eczema may be less noticeable. Within minutes of the food being eaten, there is a reaction such as hives, or redness or swelling around the mouth. Older children and adults feel a very unpleasant tingling in their mouth and have a strong urge to spit the food out. The reaction may go on to cause swelling around the eyes, and the eyes and nose may water.
Vomiting is common.
In a severe reaction, the swelling may spread to the airways and cause difficulty breathing - sometimes the reaction can cause an asthma attack. In severe cases, hives may spread all over the body and the swelling may be so bad that the person goes into shock. Foods most likely to cause severe reactions are peanuts, nuts, milk, egg and fish. 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.