Experts can classify allergic rhinitis by how often a person has it and how severe it is. Allergic rhinitis is:
- Intermittent if you have symptoms fewer than 4 days a week or fewer than 4 weeks a year.
- Persistent if you have symptoms 4 or more days a week and 4 or more weeks a year.
- Mild if your symptoms do not affect your sleep, daily activities, and work or school. You have no symptoms that bother you a lot.
- Moderate to severe if your symptoms do any one of the following:
- Interfere with your sleep
- Make daily activities or work or school difficult
- Bother you a lot
Many experts in the United States classify allergic rhinitis according to the kind of allergens a person reacted to and when the reactions occurred.
Seasonal allergic rhinitis (SAR). A seasonal allergy occurs at the same time each year and is often called hay fever. The most common allergens in seasonal allergies are windblown pollens from trees, grasses, or weeds, so the symptoms of a seasonal allergy usually occur when certain plants are in bloom. (Some types of mold also occur seasonally and may cause similar symptoms.)
Perennial allergic rhinitis (PAR). A year-round (perennial) allergy occurs any time during the year. The symptoms of a year-round allergy may be more severe in winter, when people spend more time indoors. The most common causes of perennial allergies are dust mites, animal dander, cockroaches, or mold.
Occupational allergic rhinitis (OAR). Occupational allergic rhinitis is caused by an allergic reaction to a substance present in the workplace, such as grain, wood dust, chemicals, or lab animals.