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  • Disease

    Agammaglobulinemia

    Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

    Agammaglobulinemia is a disorder passed down through families in which a person has very low levels of protective immune system proteins called immunoglobuli...

  • Injury

    Allergic reactions

    Dermatographism is a condition where lightly scratching the skin raises wheals or welts. Histamine is released, which causes the small blood vessels (capillaries) to dilate, producing redness and localized swelling.

    Allergic reactions are sensitivities to substances called allergens that come into contact with the skin, nose, eyes, respiratory tract, and gastrointestinal...

  • Disease

    Allergic rhinitis

    Allergic rhinitis, or hay fever, is a collection of symptoms, predominantly in the nose and eyes, to allergens such as dust, dander and pollen. The sensitized immune system produces antibodies to these allergens, which cause chemicals called histamines to be released into the bloodstream, causing itching, swelling of affected tissues, mucus production, hives, rashes, and other symptoms. Symptoms vary in severity from person to person.

    Allergic rhinitis is a diagnosis associated with a group of symptoms affecting the nose. These symptoms occur when you breathe in something you are allergic ...

  • Disease

    Allergies

    Hives (urticaria) are raised, red, itchy welts, seen here on the arm.  The majority of urticaria develop as a result of allergic reactions.  Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs,  malignancy, or other causes.

    An allergy is an immune response or reaction to substances that are usually not harmful. Allergies are pretty common. Both genes and environment play a role....

  • Test

    Allergy testing - skin

    Intradermal allergy testing is another method of skin testing to help determine whether an individual is allergic to a specific allergen. The test involves injection of a small amount of the suspected allergen under the surface of the skin. After about 20 minutes the area is examined for a reaction at the site. A typical reaction looks like a small hive with swelling and redness. The intradermal test is more sensitive than the skin prick test and can usually provide more consistent results.

    Allergy skin tests are tests used to find out which substances cause a person to have an allergic reaction. There are three common methods of allergy skin te...

  • Disease

    Anaphylaxis

    Allergic reaction to bee stings occurs when a person becomes sensitized to the venom from a previous sting. This reaction is different from the reaction to the poison in the bite of a black widow spider, which injects a potent toxin into the blood. Ordinarily, bee venom is not toxic and will only cause local pain and swelling. The allergic reaction comes when the immune system is oversensitized to the venom and produces antibodies to it. Histamines and other substances are released into the bloodstream, causing blood vessels to dilate and tissues to swell. Severe reactions can lead to anaphylactic shock, a life-threatening series of symptoms including swelling of the throat and difficulty breathing. Persons who develop an allergy to bee stings should carry prescription bee sting kits to counteract the reaction to bee venom.

    Anaphylaxis is a life-threatening type of allergic reaction. Anaphylaxis is a severe, whole-body allergic reaction to a chemical that has become an allergen....

  • Disease

    Angioedema

    Angioedema is swelling that is similar to hives, but the swelling is under the skin instead of on the surface. Hives are often called welts. They are a surf...

  • Test

    Anti-smooth muscle antibody

    Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

    Anti-smooth muscle antibody is a blood test that detects the presence of antibodies against smooth muscle. A blood sample is needed. This may be taken throug...

  • Test

    Antibody titer

    The antibody level in the blood is a reflection of the body's past experience or exposure to an antigen, or something that the body does not recognize as self. Every living cell has different protein markers on its surface called antigens, and the body's immune system identifies those cells that are not part of its structure by those surface proteins.

    Antibody titer is a laboratory test that measures the level of antibodies in a blood sample. A blood sample is needed. For information on how this is done, s...

  • Test

    Antimitochondrial antibody

    Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

    Antimitochondrial antibodies (AMA) are substances (antibodies) that form against mitochondria, an important part of cells. Mitochondria are the energy source...

  • Test

    Antinuclear antibody panel

    Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.

    The antinuclear antibody panel is a blood test that looks at antinuclear antibodies (ANA). Antinuclear antibodies are substances produced by the immune syste...

  • Disease

    Asthma

    Spirometry is a painless study of air volume and flow rate within the lungs. Spirometry is frequently used to evaluate lung function in people with obstructive or restrictive lung diseases such as asthma or cystic fibrosis.

    Asthma is a disease that causes the airways of the lungs to swell and narrow, leading to wheezing, shortness of breath, chest tightness, and coughing. Asthma...

  • Disease

    Asthma - children

    A peak flow meter is commonly used by a person with asthma to measure the amount of air that can be expelled from the lungs. If the airways become narrow or blocked due to asthma, peak flow values will drop because the person cannot blow air out of the lungs as well. A peak flow meter can be a useful aid in monitoring a person's asthma over time and can also be used to help determine how well a patient's medications are working.

    Asthma is a disease that causes the airways to swell and get narrow. Asthma is caused by swelling in the airways. During an asthma attack, the muscles surrou...

  • Special Topic

    Asthma and allergy - resources

    The following organizations are good resources for information on asthma and allergies: Allergy and Asthma Network Mothers of Asthmatics | www.aanma.org Ame...

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