What is an allergy?
An allergy is an immune system response to a foreign substance that is harmless to most people.
What are the differences between and allergy and intolerance?
Food allergy is caused when the body mistakenly produces and IgE antibody in response to the consumption of a particular food item. When the food is next eaten or sometimes just come into contact with, it triggers an immune response which results in the release of histamine and other substances in the body. Individuals with a food allergy cannot usually tolerate any amounts of the food item. Food intolerance is more common than a food allergy but does not involve the immune system and the individual can usually tolerate small amounts of the food item.
Food allergies can cause various symptoms, depending on where in the body the histamines are released. For example, if released in the gut they may cause abdominal pain, vomiting and diarrhoea; in the skin, itching and swelling.
The onset of symptoms of food intolerance is usually slower and may be even hours after eating the food item. The symptoms may also last for several hours, even into the next day and sometimes longer. Intolerance to several foods or a group of foods is not uncommon, and it can be much more difficult to decide whether food intolerance is the cause of chronic illness, and which foods or substances may be responsible.
Food intolerance's are often self diagnosed due to mistaking similar symptoms as a response to intolerance.