Background and Epidemiology
Allergic rhinitis strikes up to 30% of adults and approximately 40% of children. In children, boys are more likely to be affected than girls, and symptoms typically develop before 20 years of age (Dykewicz, 1998). Children who exhibit perennial symptoms tend to grow into adulthood with the disorder, while up to 20% of children with seasonal symptoms will have resolution of the disorder by early adulthood (Sly, 1999).
Risk factors for the development of allergic rhinitis include residing within a polluted area, nonwhite race, and higher socioeconomic status. Other factors that have been linked with a higher likelihood of developing the disorder include: exposure to indoor allergens in early childhood, maternal smoking, and the early introduction of foods or formula during infancy (Dykewicz, 1998). There appears to be a genetic predisposition in that 60% of patients have a family history of allergic rhinitis (Cookson, 1989). Patients with a history of atopic dermatitis, eczema, asthma, or other atopic diseases are more likely to have concomitant allergic rhinitis. Approximately 20% of patients with allergic rhinitis also have asthma (Dykewicz, 1998).
A number of culprits are responsible for the triggers for allergic rhinitis. Seasonal allergic rhinitis typically occurs when levels of allergens (such as trees, pollens, grasses, weeds, and fungi) are elevated in outdoor air; seasonal allergic rhinitis also varies depending on the area of the country (AAAAI, 2005). In the United States, spring is typically when tree pollen is problematic, late spring and summer for grass pollen, and late summer or early fall for weed pollen. Mold spore levels are affected by temperature, wind, rain, and humidity (AAAAI, 2005). Outdoor molds are found on decaying vegetation and soil and are released into the atmosphere when the earth is disturbed. Perennial allergic rhinitis is present year-round and is usually noted in indoor environments. Triggers include allergens from insects, animals, molds, and house dust mites. House dust mites and molds especially prefer warm, damp environments (AAAAI, 2005). Mites are typically found in bedding, carpets, curtains, upholstered furniture, and soft toys. Molds are common in basements and bathrooms where the humidity is elevated. Molds are often present in house plants and can be isolated in piles of undisturbed papers such as old newspapers (Dykewicz, 1998). Household pets are another source of perennial allergic rhinitis, with the major allergens found in their skin or dander and saliva. Cat allergens remain airborne for up to six hours and can be detected in household dust for several months after the animal has left. An important cause of perennial allergic rhinitis in urban settings is cockroach allergens.
J Pediatr Health Care. 2005;19(4):238-244. © 2005 Mosby, Inc.
Cite this: Pediatric Allergic Rhinitis Drug Therapy - Medscape - Jul 01, 2005.