Among the most common are cow's milk, eggs, wheat, soya, peanuts and fish . Allergic reactions to food may occur anywhere in the body, but usually in the digestive system, the skin, and occasionally in the nose and lungs - the places where the special immune system cells are stationed to fight off invaders that are inhaled, swallowed or come in contact with the skin. In most cases, foods cause reactions in allergy-prone individuals if they are swallowed. In certain people, food may cause reactions such as asthma if inhaled. For example, flour can cause asthma in bakers who are allergic to this substance.
Food allergy is generally uncommon.
Skin symptoms such as eczema and hives and symptoms of the digestive tract such as stomach cramps, vomiting and diarrhoea are more common in food allergy than asthma. In general, inhaled allergens such as house-dust mites, cat fur and pollen are more likely to trigger asthma than foodstuffs. The diagnosis of food allergy is easy when the adverse reaction occurs soon after ingestion of an uncommonly used food item but more difficult if the reaction occurs several hours or days later, or if commonly used food is involved. At present there are no definite and reliable tests to diagnose food allergy. However, identifying the offending food may not be easy or it may not be possible to completely avoid it.