Diagnosing Allergies


If you suffer from sneezing, nasal congestion, runny nose, itchy eyes, hives or stuffy headache, your body's immune system is reacting to a particular substance and trying to get rid of it; this is generally known as an allergic response. Diagnosing the substances causing allergic responses will allow you to make choices that will help you avoid those allergy substances, or allergens, in the future. Given this knowledge, you can also seek treatment for specific allergies.

Immunotherapy treatment is a series of injections obtained over time. Its purpose is to allow the immune system to build up a tolerance to a particular allergen. Diagnosing allergies must precede allergy treatment; this involves either a skin or blood test to identify the substances that trigger your allergies.

Skin Tests for Diagnosing Allergies

Doctors have used skin tests for decades in their efforts to diagnose allergies. It is safe for patients of all ages, although most skin testing should be postponed until a child is three or four years old. The ImmunoCap test, available since 2001, can be run at any age.

During a skin test, a doctor places drops of the suspected allergy substance on your arm or back and then slightly pricks the skin under the drop with a small pin. The doctor then watches the area to observe reactions to allergies (such as stinging or itching or swelling). If there is a reaction, the doctor has the diagnosis of a particular allergen. There is no scarring or disfigurement from the pricks.

Blood Tests for Diagnosing Allergies

Blood tests are recommended among those for whom skin tests are not recommended. Conditions that might require a blood test include: (1) taking antihistamines, antidepressants, and heartburn medications or other medications known to interfere with test results; (2) a skin disease (such as psoriasis or eczema) on your arms and back; and (3) high sensitivity to even a small amount of a suspected allergen, which could cause anaphylactic shock (a sharp drop in blood pressure and breathing difficulties).

A blood test, sometimes referred to as the RAST test, is also recommended for diagnosing allergies to foods. Blood tests are as accurate as skin tests in diagnosing allergies, but they are often more expensive.

Finally, electrodermal screening, also known as the vega test, is another method for diagnosing allergies. It uses a Far East technique that creates an energy profile of the body. However, this method of diagnosing allergies is not deemed by the American medical community to be effective.

By Kathleen Goolsby