Diagnosis

Diagnosis

To determine the cause of allergic rhinitis, the doctor will ask a number of questions about: 

• Time of day and year of rhinitis episodes. Rhinitis that appears seasonally is typically due to pollens and outdoor allergens. If symptoms occur throughout the year, the doctor will suspect perennial allergic or non-allergic rhinitis.
• Family history of allergies.
• History of medical problems.
• In women, if they are pregnant or taking drugs that contain estrogen (oral contraceptives, hormone replacement therapy).
• Use of other medications including decongestants, which can cause a rebound effect.
• Pets.
• Any additional unusual symptoms. As examples, bloody nasal discharge and obstruction in only one nasal passage could suggest a tumor. Fatigue, sensitivity to cold, weight gain, and depression may be signs of hypothyroidism.

Physical Examination

The doctor will examine the inside of the nose with an instrument called a speculum. This is a painless examination allowing the doctor to check for redness and other signs of inflammation. The doctor will also usually check the eyes, ears, and chest.

Allergy Skin Tests

A skin test is a simple method for detecting common allergens. Patients are usually tested for a panel of common allergens. Skin tests are rarely needed to diagnose mild seasonal allergic rhinitis, since the cause is usually obvious. The skin test is not appropriate for children younger than age 3.

The procedure is as follows:

• Patients should not take antihistamines for at least 12 to 72 hours before the test. Otherwise an allergic reaction may not show up.
• Small amounts of suspected allergens are applied to the skin with a needle prick or scratch or are injected a few cells deep into the skin. The injection test may be more sensitive than the standard prick test.
• If an allergy is present, a hive (a swollen reddened area) forms within about 20 minutes.

The test is not completely accurate. For instance, a 2001 study reported that testing detected allergies in less than half of children with rhinitis. Furthermore, about 15 - 20% of people may have a skin reaction without actually having an allergy.