What is an allergy?

Allergies are very common: 2 out of 10 people in the US suffer from them, and the numbers are growing. The chances of developing allergies are influenced by heredity. If one parent has allergies, their child has a 50% chance of developing allergies also. This rises to 75%, if both parents suffer from allergies. If your parents are allergic to pet dander, you won’t necessarily be allergic to it, too. You could be allergic to something completely different.

Allergies are an unusual reaction from your immune system to any number of things in your environment which are usually harmless, for example, pet dander or a food. Your genetic make-up as well as your environment both play a part. You inherited the tendency to be allergic. The sensitivity to the substance or allergen is your own, and your immune system sees it as a threat. In the case of allergies like poison oak or certain medications, your allergies may even be learned from repeated cases of exposure to it.

Your immune system tries to fight off the perceived danger by releasing chemicals. Histamine is one of those chemicals you may be familiar with. These chemicals cause various symptoms which can include everything from hives, rashes, itching, and swelling to increased mucus production and muscle spasms.

Your immune system uses white blood cells which produce antibodies. The antibodies seek out and destroy disease causing substances. The white blood cells produce an antibody especially for that allergen. This is called “sensitization.”

When you encounter your allergen, your body begins a process to fight off this danger. It begins making an antibody called IgE which binds to the allergen. The IgE attaches to a blood cell called a mast cell. Mast cells are found in various parts of your body. The places where these are found, such as your airway and your gastrointestinal tract, are the parts of your body that will suffer the allergic reaction.

Your allergen binds to the IgE and mast cell. This antibody promotes production and release of chemicals and hormones called “mediators.” Mediators effect tissue and organs in the area of the body affected. They also activate more white blood cell defenders to the fight.

This starts a reaction that releases the chemicals such as histamine mentioned above. The chemicals released are trigger the allergic symptoms you experience and suffer from. If the release of the mediators is sudden, the allergic reaction may also be sudden and intense.

The type of allergen and where you encounter it determines what part of the body your symptoms will appear. For example, if you are allergic to nuts and eat something with nuts or nut by products in it, your symptoms will appear in your mouth, stomach and intestines.

Allergic reactions have three categories based on the degree of the reaction.

You can suffer a mild allergic reaction. A mild reaction remains in one part of your body. It could be a rash or watery eyes.

A moderate reaction has symptoms that spread to another part of the body. These might include itching or problems breathing.

A severe allergic reaction called anaphylaxis is rare. Immediate medical attention is required. This type of reaction is life threatening, fast moving, and affects the entire body. It typically begins with itching of the eyes and face. It can produce vomiting or diarrhea as well as tissue swelling that makes it difficult to breathe or swallow. Anaphylaxis usually causes a quick drop in blood pressure which can add dizziness or mental confusion to the list of symptoms. Bee stings are a common cause of this type of severe allergic reaction.

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