Diagnosis

Your doctor will perform a physical examination, take a medical history, and possibly recommend one or both of the following tests:

• Skin prick test. You're watched for an allergic reaction after small amounts of material that can trigger allergies are pricked into the skin of your arm or upper back. If you're allergic, you develop a raised bump (hive) at the site of that allergen. Allergy specialists usually are best equipped to perform allergy skin tests.
• Allergy blood test. A blood sample is sent to a lab to measure your immune system's response to a specific allergen. Also called the radioallergosorbent test (RAST), this test measures the amount of allergy-causing antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies.