What is allergic rhinitis?
Allergic rhinitis is when the nasal passages become inflamed due to the effect of allergens. Allergens such as pollen, dust and dander (particles of hair and skin that animals have shed) trigger a response in people with sensitive immune systems. The response is an increase in the production of antibodies.
When these antibodies bind to certain cells, it causes the release of histamines and other chemicals. Generally, this causes sneezing, increased mucus and for the nasal passages to become inflamed and swollen and the eyes to become watery and itchy. Some people can also develop a rash.
Air pollution can aggravate allergies. So can chemicals like chlorine. Allergic responses of one kind or another are very common, although for some it only occurs on a seasonal basis in response to certain plants like ragweed.
What is hay fever?
Hay fever is a particular kind of allergic rhinitis in which the allergens are the pollens of grass or trees.
What causes allergies?
It isn't the allergen that really causes allergies. Otherwise everyone would suffer from them. Allergies are an over-reaction by the body to the allergens. Instead of disregarding them, it treats them as a threat and launches a full scale response similar to how it responds to when you catch a cold. So it is, in a sense, an immune system problem.
There does seem to be some inherited genetic disposition toward developing allergies in that you are more likely to develop them if one parent also suffered from them. You are even more likely if both parents had it. Some have allergies as children but grow out of them. Some don't even get allergies till a little later in life.
If you are allergic to the pollen of one plant, you are more likely to develop an allergy to another type of pollen.
Disclaimer: The statements made on this page have not been evaluated by the U.S. Food and Drug Administration (FDA). They are not intended to diagnose, cure or prevent any disease. If a condition persists, please contact your physician or healthcare provider. The information provided is not a substitute for a face-to-face consultation with a healthcare provider, and should not be construed as medical advice.