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An allergic reaction is an over-response of the immune system to a particular substance or allergen (substances that cause an allergic reaction). Allergic reactions are common, and the severity of an allergic reaction can range from mild to severe to life-threatening. The most severe form of allergic reaction is an anaphylactic reaction. This type of allergic reaction is rare but rapidly becomes life-threatening and is a medical emergency.
There are a variety of types of allergies that cause allergic reactions. They include food allergies, respiratory allergies and skin allergies, which can result in such conditions as eczema and contact dermatitis.
In people who experience allergic reactions, the immune system is overzealous and reacts when they inhale, swallow or touch normally harmless substances, such as pollen or dust. The immune system is made up of special cells that circulate throughout the body to defend the body against foreign substances, such as viruses and bacteria. This over-reaction of the immune system during an allergic reaction results in the release of the chemical histamine. This causes the swelling, inflammation, and itching of tissues that are characteristic of an allergic reaction.
Almost any substance can cause an allergic reaction in a person who is sensitive to that particular substance. That substance is called an allergen. People who experience allergic reactions are often allergic to more than one substance. Common allergens include dust, pollen, mold spores, animal dander, bee stings, and cockroach or dust mite droppings. Other common allergic reactions occur in response to exposure to certain plants, such as poison ivy, and some medications, such aspirin or penicillin. Certain foods, such as eggs or milk, or chemicals and other substances, such as latex, are also common allergens that can cause an allergic reaction in a sensitive person.
When a person has an allergic reaction, exposure to an allergen can cause a wide variety of symptoms. Symptoms vary depending on the specific allergy, the type of exposure and the severity of the allergic reaction. Symptoms can affect the respiratory system, the skin and/or the gastrointestinal system. For more information on symptoms and complications, refer to symptoms of allergic reaction.
Making a diagnosis of an allergic reaction begins with performing a complete evaluation that includes a medical history, including symptoms, and a physical examination. Other tests may be done to rule out diseases or conditions with similar symptoms, such as an upper respiratory infection, sinusitis or other types of gastrointestinal diseases, such as irritable bowel syndrome.
Diagnostic testing may include skin patch testing. In a patch test, small amounts of common allergens are applied methodically to the skin to determine what substances are triggering an allergic reaction. A blood test called a radioallergosorbent test (RAST) may also be done to help identify the substance that is causing an allergic reaction. For suspected food allergies, a patient may also be asked to keep a food log to help determine the types of foods that trigger an allergic reaction.
It is possible that a diagnosis of an allergic reaction can be missed or delayed because symptoms can be similar to other conditions. For more information on misdiagnosis, refer to misdiagnosis of allergic reaction.
Patient compliance with a good treatment plan can control symptoms and repeat attacks of an allergic reaction to a degree that allows a person to live a normal, active life. Treatment may include a combination of lifestyle changes, medications, and other measures. For more information on treatment, refer to treatment of allergic reaction....more »
A diagnosis of an allergic reaction may be overlooked or delayed because symptoms may be mild in some people and/or may not occur very often. In addition, some symptoms, such as sneezing, runny nose, vomiting or diarrhea can mimic symptoms of other conditions. These include a cold, food poisoning, gastroenteritis, influenza, food intolerances, sinusitis, or eating too ...more misdiagnosis »
The following medical conditions are some of the possible
causes of Allergic reaction.
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The most effective treatment plan for an allergic reaction uses a multifaceted approach. Treatment plans are also individualized to best address the specific cause and severity of the allergic reaction, and the patient's age and medical history. In general, allergies and allergic reactions are highly treatable, although they are generally not curable. On occasion, some young children might ...Allergic reaction Treatments
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The following drugs, medications, substances or toxins are some of the possible
causes of Allergic reaction as a symptom.
Always advise your doctor of any medications or treatments you are using,
including prescription, over-the-counter, supplements, herbal or alternative treatments.
When combined, certain drugs, medications, substances or toxins may react causing Allergic reaction as a symptom. Always advise your doctor of any medications or treatments you are using, including prescription, over-the-counter, supplements, herbal or alternative treatments.
Some of the comorbid or associated medical symptoms for Allergic reaction may include these symptoms:
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Chronic lung diseases hard to diagnose: Some of the chronic lung diseases are difficult to diagnose. Even the well-knowns conditions such as asthma or lung cancer often fail to be diagnosed early. Some of the...read more »
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Normally, the immune system is the body's defense against invading agents such as bacteria and viruses. In most allergic reactions, however, the immune system is responding to a false alarm. When an allergic person first comes into contact with an allergen, the immune system treats the allergen as an invader and mobilizes to attack. The immune system does this by generating large amounts of one type of antibody. When the allergen and the antibody connect, it signals the release of powerful inflammatory chemicals. These chemicals, like histamines, cytokines, and leukotrienes, act on the tissues of various parts of the body, such as the respiratory system. The result is the symptoms commonly associated with allergies. (Source: excerpt from Allergies: NWHIC)
Normally, the immune system is the body's defense against invading agents such as bacteria and... (Source: excerpt from Allergies: NWHIC)
The list of organs typically affected by Allergic reaction may include, but is not limited to:
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This information refers to the general prevalence and incidence of these diseases, not to how likely they are to be the actual cause of Allergic reaction. Of the 49 causes of Allergic reaction that we have listed, we have the following prevalence/incidence information:
The following list of conditions have 'Allergic reaction' or similar listed as a symptom in our database. This computer-generated list may be inaccurate or incomplete. Always seek prompt professional medical advice about the cause of any symptom.
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The following list of medical conditions have Allergic reaction or similar listed as a medical complication in our database. The distinction between a symptom and complication is not always clear, and conditions mentioning this symptom as a complication may also be relevant. This computer-generated list may be inaccurate or incomplete. Always seek prompt professional medical advice about the cause of any symptom.
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Depending on the seriousness of the onset of Allergic reaction, you may want to consult one of the following medical professionals.
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