If the exact cause of allergic rhinitis is uncertain, your GP may refer you to a hospital allergy clinic for allergy testing.
The 2 main allergy tests are:
- a skin prick test – where the allergen is placed on your arm and the surface of the skin is pricked with a needle to introduce the allergen to your immune system; if you're allergic to the substance, a small itchy spot (welt) will appear
- a blood test – to check for the immunoglobulin E (IgE) antibody in your blood; your immune system produces this antibody in response to a suspected allergen
Commercial allergy testing kits are not recommended because the testing is often of a lower standard than that provided by the NHS or an accredited private clinic.
It's also important that the test results are interpreted by a qualified healthcare professional with detailed knowledge of your symptoms and medical history.
In some cases further hospital tests may be needed to check for complications, such as nasal polyps or sinusitis.
For example, you may need:
- a nasal endoscopy – where a thin tube with a light source and video camera at 1 end (endoscope) is inserted up your nose so your doctor can see inside your nose
- a nasal inspiratory flow test – where a small device is placed over your mouth and nose to measure the air flow when you inhale through your nose
- a CT scan – a scan that uses X-rays and a computer to create detailed images of the inside of the body