The symptoms of allergies are very similar to those of the common cold so it may be difficult to distinguish between the two. A good rule of thumb is when cold-like symptoms last longer than one or two weeks, or if you tend to have frequent colds, you may want to consult your doctor to discuss being tested for allergies. You may also want to consult your doctor if you notice any of the following:

• You tend to have cold-like symptoms around the same time every year. This could be a sign of seasonal allergies.
• You sneeze and your eyes itch when you are around a house pet or when you are around people who may have house pets at home.
• You have sudden sneezing or upper respiratory congestion when you enter a particular environment such as your place of work or your basement. Note that symptoms may continue even after you leave the environment.

Diagnosing Allergies

Talk to your doctor. Even if you have symptoms such as those mentioned above, only a doctor can confirm that you have allergies. More importantly, allergy testing can tell you exactly what allergens you are allergic to so you may avoid them in the future. Giving a complete and thorough history is the most important way to find out if your symptoms may be related to allergies.

Skin tests are usually conducted by an allergy specialist and involve administering a series of possible allergens into scratches made on the arm or back or by injecting them subcutaneously (under the skin). If you are sensitive to a particular allergen, it provokes a small immune response and your skin will become raised and reddened in the area where it was injected. The size of the raised area determines how sensitive you are to each particular allergen.

In some cases, the allergist may take a blood sample in order to determine the levels of IgE antibodies against specific allergens. The most common test is called RAST (for radioallergosorbent test). Blood tests are more expensive and less sensitive so they are usually reserved for people in whom skin testing is contraindicated, such as those with skin conditions like eczema or those taking medicines that might interfere with skin tests.