What is an Allergy?

We all think that we know what an allergy is – it is a reaction that our body has to a certain substance that is unique only to that person. For instance we do not consider a hangover to be an food allergy caused by alcohol, because alcohol would have this impact on anyone. A food allergy then has to be a reaction that is unique to that individual to a normally harmless substance. But what is the reason for this definition? And what is actually going on inside the body when you have such an allergic reaction? Here we will look at what an 'allergy' is and how it all works.

The reason that an allergy has to be unique to you to be counted as such is that it is something that is triggered by your immune system and the problem is actually the way your body reacts to that substance. In other words alcohol is not a food allergy because the effects of alcohol are caused by the alcohol getting into your brain and shutting down brain cells. However in the meantime a food allergy to bananas is caused by your immune system's response to the banana substance and any swelling, rash or breathing difficulties is caused by your body trying to expel the 'toxin' rather than by the banana having an effect on you.

During an allergic reaction then – the 'allergen' (the substance which is responsible for the reaction), will bind to allergic antibodies which are present on allergic cells in that person's body (including mast cells and basophils). These cells will then release chemicals such as histamine and leukotrienes which cause the symptoms of food allergy. In some cases individuals will have an allergic reaction to the histamines themselves and this can them cause a more violent reaction still.

In some cases it is possible to treat allergies with medications – for instance antihistamines can be taken in order to lessen allergic reactions to dander and pollen and many people will take these to prevent 'hayfever'. At the same time it is sometimes possible to treat allergies through desensitisation – by gradually exposing the patient to the allergen in gradually increasing quantities until the body registers it as safe and no longer triggers an allergic reaction.

Interestingly it is possible to develop any allergy at any time and it is not fully understand why allergies develop in some people and not others – indeed it is not really understood why they occur at all. What is known is that allergies do seem to run in families, and that the response is thought to have once been a protective response against parasitic infections. In some extreme cases the allergies can even occur in response to light which of course can drastically affect a person's lifestyle. While allergies can occur at any age, they are most likely to develop in childhood or young adulthood. Common allergies include allergies to bread, lactose, nuts, dander and pollen though many others exist.

This is a brief overview of how food intolerance or food allergy works. Visit the links for further information.