An allergy is an unusual response of the body’s immune system to a usually harmless substance such as pollen, food or dust. Generally, these substances pose no problem, however in those with allergies the body identifies the substance as a threat and reacts accordingly.
Food intolerances are different from allergies in that whilst the body may be struggling with a particular foodstuff - it is not treating the substance as an allergen nor producing the corresponding antibodies.
Food allergies and intolerances can be a real irritant in everyday life, manifesting as a cough, irritable bowel, headaches or rash, amongst other symptoms. Around 6-8% of children have a proven food allery (National Institute for Health and Clinical Excellence, 2011) and number of allergy sufferers in general in the UK increases by 5% each year - half of those being children. (Allergy UK)