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Signs and Symptoms of Allergies

written by: Leigh A. Zaykoski • edited by: Leigh A. Zaykoski • updated: 5/31/2010

When the immune system believes that a substance will harm your body, it goes into overdrive and produces antibodies to the substance. This produces many of the common symptoms of allergies. Learn about these symptoms to better understand your allergy condition.

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    Congestion

    Congestion typically occurs in cases of hay fever and other environmental allergies. Also referred to as a stuffy nose, congestion happens when the blood vessels inside the nose swell. This swelling causes swelling of the tissues that line the nasal cavity. Without proper treatment, nasal congestion can cause hearing problems and difficulty sleeping. Treatment for congestion caused by allergies usually involves the use of oral decongestants or nasal decongestant sprays. Because nasal sprays have addictive properties, you should use them sparingly.

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    Rash

    One of the most common symptoms of allergies is a skin rash, also known as allergic contact dermatitis. This rash forms when the skin comes into contact with an allergen or a substance that causes irritation. Common causes of allergic contact dermatitis include exposure to nickel, poison oak and poison ivy. The rash usually only forms on the area of the skin exposed to an allergen. Prevent contact dermatitis by avoiding exposure to known allergens. If you come into contact with an allergen, wash the skin immediately. Medications such as topical steroids stop the rash and eases itching and irritation.

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    Itchy Eyes

    Itchy eyes develop when an allergen comes into contact with the eyes. Mast cells in the eyes release histamine that causes swelling of the blood vessels. As the blood vessels swell, the eyes get itchy, watery and red. Examples of allergens that cause itchy eyes include pollens, pet dander, mold and dust mites. People who have high sensitivities to outdoor allergies develop seasonal conjunctivitis. Cigarette smoke and strong perfumes can worsen the allergic response of the eyes. Prevention of eye allergies involves limiting exposure to allergens, keeping windows closed and wearing glasses when outdoors.

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    Itchiness

    Itchy skin, also known as pruritis, is a common symptom of allergies. This symptom usually appears when the skin comes into contact with an allergen. Even using new soaps or detergents can trigger an allergic response that causing itching and irritation. One of the most common problems caused by itching is the itch-scratch cycle. When you scratch your skin, it may irritate the area and cause even more itching. More itching leads to more scratching, and the cycle continues. Allergies can also cause itchy hives, also known as urticaria. Hives appear as pale red bumps after skin exposure to allergens. Several hives can grow together to develop plaques on the skin. These hives may last up to one day before they disappear.

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    Anaphylaxis

    Anaphylaxis is the most serious sign of allergy. This occurs when the entire body gets involved in an allergic reaction. After allergen exposure, the entire body develops sensitivity to the allergen. This causes the body tissues to release histamine, producing several anaphylaxis symptoms. These signs and symptoms include abnormal breathing sounds, confusion, anxiety, hives, itching, nausea, vomiting, slurred speech, skin redness, wheezing, difficulty breathing and nasal congestion. Anaphylactic shock requires emergency medical treatment, so call your local emergency services number as soon as someone exhibits signs of this condition. While you wait for help to arrive, administer basic first aid to prevent serious complications.