allergicreaction

What is allergic reaction?


An allergic reaction is the body's way of responding to an "invader." When the body senses a foreign substance, called an antigen, the immune system is triggered. The immune system normally protects the body from harmful agents such as bacteria and toxins. Its overreaction to a harmless substance (an allergen) is called a hypersensitivity reaction, or an allergic, reaction. Anything can be an allergen. Common dust, pollen, plants, medications, certain foods, insect venoms, animal dander, viruses, or bacteria are examples of allergens. Reactions may occur in one spot, such as a small skin rash or itchy eyes, or all over, as in a whole body rash. A reaction may include one or several symptoms. In rare cases, an allergic reaction can be life-threatening (known as anaphylaxis). Each year in the United States, over 400 people die from anaphylactic reactions to penicillin, and nearly 100 Americans die from anaphylactic reactions to insects, according to the Asthma and Allergy Foundation of America (AAFA).

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Also known as Allergy, Allergies, Allergic Reactions, Hypersensitivity, Hypersensitivities
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Allergic reactions

Allergic reactions are serious and potentially life-threatening, and can cause injury to tissues throughout the body. Some people have hypersensitive immune systems that overreact to otherwise harmless things such as bee stings, foods, medications, and latex. Reactions range in severity: one person may break out in hives after eating shrimp, another may feel his or her throat closing up. In some cases, the person might pass out or have a heart attack. Without immediate medical treatment, allergic reactions can be fatal.

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Allergies

Allergies occur when your immune system reacts to a foreign substance such as pollen, bee venom or pet dander.

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Allergies

Allergy is the term used to describe an adverse (bad) reaction that the body has to a particular substance. Most things that cause allergies are not harmful, and have no affect on people who are not allergic.

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Allergies

An acquired hypersensitivity to a substance (allergen) that does not normally cause a reaction. It is essentially an antibody-antigen reaction but in some cases the antibody cannot be demonstrated. The reaction is due to the release of histamine or histamine-like substances from injured cells. There may be a genetic predisposition to acquire a particular allergy. The number of exposures necessary to produce enough antibodies to cause an allergy varies. An allergy may occur the second time a person is exposed to a particular allergen, or may not occur until years later when repeated exposures have produced sufficient antibodies. Manifestations most commonly involve the respiratory tract or the skin. Allergic conditions include eczema, allergic rhinitis or coryza, hay fever, bronchial asthma, urticaria (hives), and food allergy. The immune system is a highly complex defense mechanism that helps us to combat infection. It does this by identifying "foreign bodies" and mobilizing the body's white blood cells to fight the infection. In some people, the immune system wrongly identifies a non-toxic substance as an invader, and the white blood cells overreact and do more damage to the body than the invader.

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Allergic reaction definition - Allergies: Allergy Symptoms ...

Mar 26, 1998 ... Allergic reaction: The hypersensitive response of the immune system of an allergic individual to a substance. ...

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Anaphylaxis (Severe Allergic Reaction) Symptoms, Causes, Diagnosis ...

Mar 11, 2011 ... Anaphylaxis refers to a rapidly developing and serious allergic reaction that affects a number of different areas of the body at one time. ...

Read more on www.medicinenet.com

Allergic reactions Information on Healthline

The immune response that causes an allergic reaction is similar to the response ... Once a person has had an allergic reaction (is sensitized), even a very ...

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Allergic Reactions - AAAAI

While these are symptoms of some types of allergic disease, an allergic reaction is actually a result of a chain reaction that begins in your genes and is ...

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Serious Allergic Reactions (Anaphylaxis)

A person with severe allergies can be at risk for a sudden, serious allergic reaction called anaphylaxis. This reaction can seem scary, but the good news is ...

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eMedicine Online Text: Allergic Reaction

Mar 15, 2010 ... Overview: Anaphylaxis is a severe allergic reaction that is rapid in onset and may cause death. There are usually prominent dermal and ...

Read more on emedicine.medscape.com

Contents

Allergic reactions
Allergic reactions are sensitivities to substances, called allergens, that are contacted through the skin, inhaled into the lungs, swallowed, or injected.

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Hypersensitivity
An allergy is a reaction of your immune system to something that does not bother most other people. People who have allergies often are sensitive to more than one thing. Substances that often cause reactions are How do you get allergies Scientists think both genes and the environment have something to do with it. Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm.

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Allergies
An allergy is an exaggerated immune response or reaction to substances that are generally not harmful. See also: Allergic conjunctivitis Allergic reactions Allergy testing Allergy to mold, dander, dust Atopic dermatitis (eczema) Contact dermatitis Drug allergies Food allergies Hay fever (allergic rhinitis)

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Allergy
Treats stuffy nose, sneezing, runny nose, and sinus congestion caused by hay fever, colds, or flu.

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Severe Allergic Reaction
Anaphylaxis is a severe allergic reaction that occurs rapidly and causes a life-threatening response involving the whole body. This reaction can lead to difficulty breathing and shock ultimately leading to death.

Chemical burn or reaction
Depending on the type of exposure, the symptoms may include: Abdominal pain , Breathing difficulty , Bright red or bluish skin and lips, Convulsions (seizures), Dizziness , Headache , Hives, itching, swelling, nausea, vomiting, or weakness resulting from an allergic reaction , Irritability, Pain where the skin has come in contact with the toxic substance, Rash, blisters, burns on the skin, Unconsciousness

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Interstitial nephritis
Interstitial nephritis is a kidney disorder in which the spaces between the kidney tubules become swollen (inflamed). The inflammation can affect the kidneys' function, including their ability to filter waste.

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Allergic rhinitis
Allergic rhinitis is a collection of symptoms, mostly in the nose and eyes, which occur when you breathe in something you are allergic to, such as dust, dander, or pollen. This article focuses on allergic rhinitis due to outdoor triggers, such as plant pollen. This type of allergic rhinitis is commonly called hay fever. For information on other types of allergies, see: Allergies Allergy to mold, dander, dust Asthma

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Allergic Reaction Symptoms, Causes, Signs, Treatment and ...
An allergic reaction is the body's way of responding to an "invader." When the body senses a ... What were the symptoms and signs of your allergic reaction? ...

Allergic Reaction-Topic Overview
Jun 26, 2009 ... Allergies are an overreaction of the body's natural defense system that helps fight infections (immune system).

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Allergy - Wikipedia, the free encyclopedia
Allergic reactions occur to normally harmless environmental substances known as allergens; these reactions are acquired, predictable, and rapid. ...

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