Auckland DHB Clinical Immunology and Allergy
Public Service, Allergy and Immunology
Allergic Rhinitis and Hay Fever - Causes
What is allergic rhinitis or rhinoconjunctivitis?
Allergic rhinoconjunctivitis is the inflammation of the lining of the nose and eyes due to allergy. It causes a blocked, runny and itchy nose, sneezing and itchy running eyes.
For some people bad rhinitis can be associated with worsening asthma so it is hard to breathe.
What causes allergic rhinitis? - Inhalant allergens
Allergic rhinoconjunctivitis (hay fever) is caused by a reaction to inhalant allergens. An allergen is a tiny particle that people are often allergic to. Inhalant allergens are particles that travel through the air to cause allergy. Given that they travel through the air, inhalant allergens tend to land on people's eyes or in the nose and mouth. When this happens inhalant allergens cause the following symptoms:
- allergic rhinitis - (running, itchy nose and sneezing)
- allergic conjunctivitis - (running, itchy eyes)
- itching in the mouth, ears and palate for some people
Some typical inhalant allergens are house dust mite, grasses, plantain (a weed), tree pollen and cat and dog hair.
Hay fever is allergic rhinitis due to grass allergy and is mostly during spring/summer.
Allergic rhinitis due to dust mite lasts year round and can be worse overnight, in the mornings or around vacuuming or dusty environments. Cat/dog allergy can also cause year round symptoms.
Testing for allergic rhinitis
The specific allergen (the thing that you are allergic to) may be identified by skin prick tests.
This involves placing a drop of the allergen on your skin and then scratching your skin through the drop. If you are allergic, your skin will become red and swollen at the site.
Skin tests are only of value if interpreted with respect to a careful history of a patient's clinical symptoms. They are not a diagnosis by themselves.
Treatment of allergic rhinitis
Click here for information on the treatment of rhinitis.