Which foods are the most common causes of allergic reactions? The majority of allergic reactions to dietary components are caused by a small number of foods, namely: * Cow’s milk * Hen’s eggs * Peanuts * Tree nuts * Soya beans * Soya products * Fish * Shellfish, prawns * Gluten containing cereals eg. Wheat * Citrus fruits In children, it has been estimated that nine out of ten reactions are to milk, soya, peanuts, tree nuts, or wheat gluten. Many of these reactions reduce after early childhood. A majority of allergic reactions in adults result from sensitisation to shellfish, fish, peanuts, and tree nuts. It is unusual for food allergy to begin in adulthood.