Hay fever is a common form of allergic rhinitis, an allergy caused by reaction to an allergen. Allergens include pollens, molds, wood dust, mites, certain foods and pet danders. Unlike food and animal allergies, hay fever is considered a seasonal allergy because it depends on the amount of pollen in the air, which varies by region and month. "Seasonal allergic rhinitis' is the term used by researchers to describe hay fever.
Prevalence
Nearly 500 million people worldwide have allergic rhinitis, and the incidence is rising, reports the Allergic Rhinitis and its Impact on Asthma workshop, an international committee of experts known as ARIA. The condition affects up to 20 percent of adults and up to 40 percent of children. People are most likely to develop hay fever before the age of 20.
Risk Factors
The risk for allergic rhinitis and hay fever is higher in people who have asthma or other allergies or have a close relative with these conditions, according to the Mayo Clinic. The risk for severe hay fever is higher for people who live closest to pollens, reports ARIA. Exposure to cigarette smoke in the first year of life and chronic exposure to allergens such as certain grasses also boost susceptibility, according to the Mayo Clinic.
Symptoms
Symptoms of allergic rhinitis and hay fever include runny nose, watery eyes, sneezing and cough, as well as itchy eyes, nose and roof of the mouth, reports the Mayo Clinic. Nasal congestion may occur as well, especially in young children, reports ARIA. Hay fever signs usually appear immediately upon exposure to the substance causing the allergy, according to the Mayo Clinic. For most people, the symptoms of hay fever change and diminish slowly with age.
Complications
Allergic rhinitis can cause complications, especially if it goes untreated or improperly managed. It can cause insomnia and other sleep disturbances, leading to daytime fatigue and reduced productivity at work and school, according to ARIA. Other problems include worsening of asthma symptoms such as cough and wheezing, reports the Mayo Clinic. In children, hay fever may aggravate ear infections.
Management
The simplest way to treat allergic rhinitis, including hay fever, is to avoid the substance causing it. This includes shutting windows, using air purifiers and avoiding exposure when pollen counts are high, such as the morning or when wheat is being cut. Over-the-counter medications can alleviate symptoms in some sufferers; however, patients with severe or persistent allergies may require a combination of medications, including prescription drugs, reports the Mayo Clinic.
References
- http://www.mayoclinic.com/health/hay-fever/ds00174
- Allergy (journal): "Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 Update"; Bousquet J, et al
