The immune system is a complex network of specialized organs and cells that defend the body against foreign invaders, like toxins, viruses, or even other humans’ blood and tissue cells. When exposed to outside elements like bacteria or viruses, the immune system activates white blood cells, creating antibodies to fight off these invaders.
An allergy (or allergic reaction) occurs when the immune system mistakes a typically harmless substance for dangerous toxin, then produces an antibody called "immunoglobulin E,” more commonly known as "IgE". Immunoglobulin E defends against very specific parasitic infections. However, people who live in more developed countries, like the United States and Britain, usually remain unexposed to these parasites throughout their lives. Most people with absent or relatively low IgE do not suffer from allergies.
What Happens in an Allergy Attack?
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When a person encounters an allergen to which they are allergic, the person’s immune system manufactures immunoglobulin E (IgE) in order to fight off the offending allergen. Each allergen will have a specific IgE antibody to fight off that specific trigger. In the case of someone who is allergic to cats, when that person interacts with a feline, their immune system creates an “anti-cat” IgE antibody, tailored to destroy the specific type of feline cells which have invaded the allergic person’s system. If the same person is also allergic to pollen comes in contact with pollen grains, then an "anti-pollen" IgE antibody will also be produced by their immune system to guard against the pollen.
Each time immunoglobulin E (IgE) is produced, the IgE antibody molecules attach themselves to mast cells, found in large numbers within the eyes, nose, lungs, intestines, and immediately beneath the skin. These mast cells contain several chemicals, including a substance called histamine. Mast cells release histamine into the blood stream after IgE antibodies attach to them, and then trap invading allergens. Upon trapping the invading allergens, allergic reactions such as hives, welts, or lung spasms may manifest. When the immune system releases histamines into the body, a person may develop a runny nose, sneezing, watery eyes, itching, hives, or wheezing. Doctors recognize these unsavory reactions as allergy symptoms.
In some cases, reactions can occur in multiple locations throughout the body. Welts or hives may appear, spasm in the lungs may cause coughing or wheezing, the throat and tongue may swell. The occurrence of anaphylaxis (severe allergic reactions) may be fatal.
Can Allergies be Controlled?
Avoidance remains the best defense against allergies. Often allergy patients cannot avoid encountering their allergy triggers. Those who are allergic to pollen must breathe and exist in the outdoors even when the pollen counts are high. For those allergy sufferers, doctors may prescribe medication to relieve allergy symptoms. Allergy medicines may help relieve symptoms, but they cannot alter the body’s natural allergy immune response. If symptoms cannot be controlled or if someone is at risk of anaphylaxis (severe allergic reactions), allergy shots may be prescribed. People often take allergy shots because they don't want to take pill medications every day. Allergy shots may put your allergies into remission.