Allergy Diagnosis

People with allergy symptoms, such as the runny nose of allergic rhinitis, may at first suspect they have a cold, but the “cold” lingers on. Testing for allergies is the best way to find out if a person is allergic.

Skin Tests

Allergists (doctors who specialize in allergic diseases) use skin tests to determine whether a person has IgE antibodies in the skin that react to a specific allergen. The allergist will use weakened extracts from allergens such as dust mites, pollens, or molds commonly found in the local area. The extract of each kind of allergen is injected under a person’s skin or is applied to a tiny scratch or puncture made on the arm or back.

Skin tests are one way of measuring the level of IgE antibody in a person. With a positive reaction, a small, raised, reddened area, called a wheal (hive), with a surrounding flat red flush, called a flare, will appear at the test site. The size of the wheal can give the doctor an important diagnostic clue, but a positive reaction does not prove that a particular allergen is the cause of symptoms. Although such a reaction indicates that IgE antibody to a specific allergen is present, respiratory symptoms do not necessarily result.


Blood Tests

Skin testing is the most sensitive and least costly way to identify allergies. People with widespread skin conditions like eczema, however, should not be tested using this method. There are other diagnostic tests that use a blood sample to detect levels of IgE antibody to a particular allergen. One such blood test is called the radioallergosorbent test (RAST), which can be performed in some patients or when eczema is present or if a person has taken medicines that interfere with skin testing. Blood taken from a single draw can be used to test for many different possible allergens.


This information was adapted from the National Institute of Allergy and Infectious Diseases handouts on airborne allergens and food allergy.

Common Allergies

  • Pollen

    Each spring, summer, and fall, tiny pollen grains are released from trees, weeds, and grasses. These grains hitch rides on currents of air. Although the mission of pollen is to… Read More

  • Mold

    There are thousands of types of molds and yeasts in the fungus family. Yeasts are single cells that divide to form clusters. Molds are made of many cells that grow… Read More

  • House Dust and Dust Mite

    Dust mite allergy is an allergy to a microscopic organism that lives in the dust found in all dwellings and workplaces. House dust, as well as some house furnishings, contains… Read More

  • Food

    Food allergy affects up to 6 to 8 percent of children under the age of three and 2 percent of adults. If you have an unpleasant reaction to something you… Read More

  • Animal

    Household pets are the most common source of allergic reactions to animals. Many people think that pet allergy is provoked by the fur of cats and dogs. Researchers have found,… Read More
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We can help you manage your allergies.

  • Allergy Diagnosis
  • Allergy Prevention
  • Allergy Treatment

People with allergy symptoms, such as the runny nose of allergic rhinitis, may at first suspect they have a cold, but the “cold” lingers on. Testing for allergies is the best way to find out if a person is allergic.

… Read More

Pollen and Molds

Complete avoidance of allergenic pollen or mold means moving to a place where the offending substance does not grow and where it is not present in the air. Even this extreme solution may offer only temporary relief

… Read More

Medicines

If you cannot adequately avoid airborne allergens, your symptoms can often be controlled by medicines. You can buy medicines without a prescription that can relieve allergy symptoms. If, however, they don’t give you relief or they cause unwanted side

… Read More