Although the word "Allergy" is commonly used to describe any unpleasant reaction to a drug, food, insect sting or chemical, this can be misleading. The word should only really be used to describe a reaction produced when the body meets a normally harmless substance, which has been "remembered" from a previous exposure and subsequently produces the "IgE" antibody.

"Sensitivity" is a reaction to a substance, which is an exaggeration of a normal side effect produced by that substance. For example, reliever inhalers used in asthma, if given at too high a dose in a particular individual may cause them to "shake".

"Intolerance" happens when unpleasant symptoms occur after eating a substance, which your body cannot handle because the digestive system does not produce sufficient quantities of a particular enzyme/chemical, which is needed to break down the food and aid digestion.

The causes of symptoms need to be correctly diagnosed so that the management and treatment for either allergy, sensitivity or intolerance can be appropriately taken.