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Risk Factors and Causes


Dr. Green
People develop allergic rhinitis when their body's immune system becomes sensitized and overreacts to an allergen that they breathe in. Captain Miller, can you tell us about what kinds of allergens typically cause allergic rhinitis?

Captain Miller
Of course, Dr. Green. Seasonal allergic rhinitis, in which symptoms occur during a particular season, is usually caused by sensitivity to outdoor allergens. Common outdoor allergens include:

  • Pollen from weeds
  • Airborne mold spores
  • Pollen from grasses, and
  • Pollen from trees

Ragweed is a common allergen in the late summer and early fall. Grasses and tree pollen are the most common triggers in the spring.

When allergic rhinitis symptoms occur year-round, it's called perennial allergic rhinitis. This type of allergic rhinitis is typically caused by sensitivity to indoor allergens, such as:

  • Dust mites
  • Pet hair or dander
  • Cockroaches, and
  • Mold

Allergic rhinitis is a type of allergic reaction. Allergic reactions are a result of the immune system mistaking an allergen for a dangerous substance. The immune system then produces special antibodies to fight against the allergen. Every time a person is exposed to the allergen, those antibodies release a number of chemicals, such as histamine, that cause allergy symptoms.

Sometimes rhinitis symptoms may not be related to an allergy at all. This is called non-allergic rhinitis, and it's often triggered by common irritants. Examples of common irritants include:

  • Cigarette smoke
  • Strong odors, such as perfume, hair spray, and fumes
  • Cosmetics
  • Laundry detergents
  • Cleaning solutions
  • Pool chlorine
  • Car exhaust, and
  • Other air pollutants