Prevalence of allergic sensitization versus allergic rhinitis symptoms in an unselected population.

Background: Allergic rhinitis (AR) is the most common allergic disorder and its prevalence has significantly increased worldwide, nowadays affecting up to 40% of the population in young adults. The objective of the present survey was to evaluate the prevalence of allergic sensitization and the prevalence of clinically diagnosed AR in a sample of the Belgian population, and to estimate the effect of age and gender.

Methods: We performed a cross-sectional population-based study at an annual public fair in Ghent. Participants underwent a skin prick test (SPT) to 3 aeroallergens: a mix of trees (hazel, alder, and birch), grass pollen, and house dust mite (HDM). The clinical relevance of sensitization was assessed by relating relevant symptoms of AR to the corresponding SPT.

Results: A total of 2,320 participants (1,475 females, median age 44.7 years, range 3-86) were included in this study. The standardized prevalence rates of sensitization were 13.2% for tree mix, 25.9% for grass pollen, and 25.9% for HDM. Sensitization to at least one of the allergens was present in 40.3% of the subjects. Symptomatic sensitization related to trees was reported in 9.7% of cases, grass-related AR was 17.6%, and HDM-related AR was 17.1%. The overall prevalence of AR was 30.9%.

Conclusion: In this study we demonstrated a 40.3% prevalence of a positive SPT to one or more common aeroallergens. A clinical diagnosis of AR was present in 30.9% of cases, peaking in the third and fourth decades of life. It is to be expected that in the next decades, when this generation grows older, the general AR prevalence will further increase.