Allergic rhinitis is a common problem in many countries. The incidence of Allergic rhinitis is about 10-25% of the population and increasing worldwide especially in large cities where air pollution is the main problem causing respiratory illness. In Thailand, the surveys of allergic rhinitis on children were found about 13-44% while the prevalence of allergic rhinitis in Thai adults was as high as 20%. The information of the prevalence of Allergic rhinitis in the suburban area has not been continuously done especially in the adult population.
Objective: To present study the prevalence of allergic rhinitis and other atopic diseases and to determine the aeroallergen sensitivity of allergic patients in suburban area.
Material and Method: Observational descriptive cross-sectional Study as one-stage cluster sampling, Using ISAAC questionnaires interviewed adults at Wat Intaram community, Hua Raeu, Phra Nakhon Si Ayutthaya District, Phra Nakhon Si Ayutthaya Province, Thailand during September-October 2008. Participants who had allergic rhinitis symptoms described in the questionnaires were enrolled to perform the skin prick test voluntary to determine the aeroallergen sensitivity.
Results: There were 324 subjects, female 64.8% and male 35.2%. Age ranges between 20-66 years old (mean 42.2). The prevalence of allergic rhinitis, asthma and chronic pruritic rash were 37.7%, 16%, 21.3% and history of allergic rhinitis, asthma and chronic pruritic rash within 12 months were 32.1%, 10.5%, 17.3%. The sensitized allergen was Mixed mite (62.2%), Mixed cockroach (61.1%), House dust (48.9%), Cat (37.8%), Johnson glass (30.0%), Dog (20.0%), Careless weed (20.0%), Mixed mold (12.2%), Cotton (7.8%) and Feather (6.7%).
Conclusion: The present study revealed that the prevalence of allergic rhinitis and atopic diseases has been increasing in number when compared with previous reports. The most common sensitized allergen was Mite mix, similar to other studies, but Mixed cockroach was found significantly higher.

Keywords: Allergic rhinitis, Prevalence, Skin prick test, Allergen