Early-life risk factors and allergic rhinitis: comparing European and US data.

Allergic rhinitis has been shown to affect 3% to 19% of subjects in various epidemiologic studies of different populations. Eighty percent of those with allergic rhinitis experience symptoms by the age of 20 years, and 40% have symptoms by the age of 6 years. Allergic rhinitis is a substantial burden on both adult and pediatric patients, not only because of the bothersome physical symptoms but also because of the emotional and social effects., 3 It is also closely linked with the development of asthma. Investigation into early-childhood factors influencing the development of allergic rhinitis raises the possibility of altering its natural history and decreasing this significant negative effect.