Exams and Tests

Your doctor can usually diagnose allergic rhinitis by examining you and asking you questions about your symptoms, activities, and home. If your doctor thinks that you have allergic rhinitis, and you don't have complications, he or she may decide to treat your symptoms without doing lab tests. The doctor will then check your symptoms again later.

But you may need further testing if:

• You and your doctor need to find out exactly what things you are allergic to so that you can take steps to avoid them.
• Treatment is not helping your symptoms.
• You have severe symptoms.
• You are considering allergy shots (immunotherapy).

For further testing, your doctor may suggest that you have:

• Allergy tests. For example, a skin test can show how your skin reacts to an allergen. Or a blood test can measure the level of immunoglobulin E (IgE) antibodies, which your body makes in response to certain allergens.
• Nasal cytology (nasal smear) testing. This test shows if the drainage from your runny nose contains eosinophils, a type of white blood cell that may be in people who have allergies.

These tests can help your doctor know whether allergic rhinitis is causing your symptoms and find the best treatment. They can also help your doctor see if you have complications, such as sinusitis or asthma.

Other tests for allergies

In most cases, you do not need testing. But your doctor may suggest some tests to make sure that another condition is not causing your symptoms. These tests include:

• Imaging tests, such as X-rays, CT scans, and MRIs. These tests can show if you have a sinus infection (sinusitis), chronic inflammation (thickening) of the sinus lining, structural defects of the nose, or, in rare cases, cancer.
• Rhinoscopy or nasal endoscopy. Both of these tests look for nasal polyps and other problems that may block the nasal cavity.
• Mucociliary clearance testing. This test looks for abnormal cilia in people who have very thick nasal discharge. Cilia are tiny hairs on the lining of the nasal passages. These tiny hairs beat back and forth to remove particles from the nose. Certain rare diseases can cause problems in the cilia, which can lead to more nasal discharge.