An allergic person may experience many different types of symptoms; often the typical symptoms of any inflammation, like redness, swelling and increased fluid production that cause symptoms like a runny or blocked-up nose, weeping eyes, etc. Actually, this is exactly what allergy is - an underlying inflammation.

IgE is an antibody, designed to protect us from foreign, potentially dangerous substances by patrolling the blood stream and by functioning as probing "masts" on mast cells.

It is also the main antibody involved in allergies. You might even say that allergy is IgE mediated.

In an allergic person, IgE is continuously produced by blood cells called plasma cells.

Why do I have IgE?
IgE is specific. That means IgE to cat can only trigger an allergic reaction on exposure to cat and IgE to grass pollen can only trigger an allergic reaction on exposure to grass pollen. (Well almost only).

Thus, when an allergy prone person is exposed to an allergen for the first time, they may start to produce IgE antibodies that are specific to that particular allergen.

Once such a person has specific to IgE patrolling the blood stream, he or she may in the future have an allergic reaction to that allergen.

The reason mast cells are called "mast cells" is that they have antibodies on their surface. Like little "masts" these antibodies stick out of the cell, acting as detectors when the cell probes the surroundings for potentially dangerous substances.

When an allergic person is exposed to something he or she is allergic to, these antibodies are short circuited and the cell breaks open to release its symptom causing content.

Mast cells are activated when they are covered in antibodies that upon contact with an allergy trigger release histamine. The antibodies are called immunoglobulin E - or just IgE.

Allergy symptoms are caused by histamine and other powerful allergy mediators that initiate an inflammatory response to protect the body. Histamine is released from cells, called mast cells, that are present in the skin and the airways.