Some people have a reaction to particular food proteins.
Their immune system produces antibodies which can cause symptoms such as itching, vomiting, cramps and diarrhoea. Usually only one or two foods are involved, for example, milk, eggs, peanuts or fish. The symptoms occur within minutes or a few hours of eating the food protein. A severe allergic reaction requires urgent medical attention. Treatment is by complete avoidance of the food containing the protein which causes the reaction.