BACKGROUND: Allergic rhinitis affects a significant proportion of the European population. Few surveys have investigated this disorder in Greek adults. Our objective was to describe the characteristics of patients with allergic rhinitis in an adult outpatient clinic in Thessaloniki, Greece.METHODS: We studied the medical records of adult patients referred to a Clinical Immunology outpatient clinic from 2001 to 2007. The diagnostic procedure was not changed during the whole study period, including the same questionnaire used at the time of diagnosis, skin prick tests, and serum specific IgE.RESULTS: A total of 1851 patient files with diagnosed allergies were analysed and allergic rhinitis was confirmed in 711 subjects (38.4%). According to ARIA classification, persistent allergic rhinitis was more prevalent than intermittent (54.9% vs. 45.1%), while 60.8% of subjects suffered from moderate/severe disease. In multivariable analysis, factors associated with allergic rhinitis were age (for every 10 years increase, OR: 0.84, 95% CI: 0.77-0.91; p<0.001); working in school environment (teachers or students) (OR: 1.46, 95% CI: 1.05-2.02; p=0.023); parental history of respiratory allergy (OR: 2.41, 95% CI: 1.69-3.43; p<0.001); smoking (OR: 0.71, 95% CI: 0.55-0.91; p=0.007); presence of allergic conjunctivitis (OR: 6.16, 95% CI: 4.71-8.06; p<0.001); and asthma (OR: 2.17, 95% CI: 1.57-3.01; p<0.001). Analysis after multiple imputation corroborated the complete case analysis results.CONCLUSIONS: Allergic rhinitis was documented in 38.4% of studied patients and was frequently characterised by significant morbidity. Factors associated with allergic rhinitis provide insight into the epidemiology of this disorder in our region. Further studies on the general population would contribute to evaluating allergic rhinitis more comprehensively.