BackgroundThe prevalence of allergic rhinitis (AR), an environment- and lifestyle-dependent condition, has been constantly increasing in Korea. Although the environment and lifestyle of the Korean people have recently undergone rapid changes, corresponding changes in the characteristics of AR patients have not been well documented. Therefore, we aimed to outline the changes in allergens and clinical manifestations of AR in Korean patients from the 1990s and 2010s.MethodsWe reviewed 1447 and 3388 AR patients who visited the same tertiary hospital in the 1990s and 2010s, respectively. All patients were diagnosed with AR based on the presence of characteristic symptoms, positive skin prick test results, and answered a symptom questionnaire at the time of visit. We compared differences in the allergens and results of the symptom questionnaire between the two sets of patients.ResultsWhen compared with the 1990s, the rate of sensitization to house dust mites, cockroaches, Aspergillus, Alternaria, and tree pollen significantly increased and that to cat fur significantly decreased in patients from the 2010s (all P < 0.05). Male predominance was observed with two peaks in the age distribution of patients from the 2010s. The proportion of patients with moderate-to-severe nasal obstruction and itching of the nose/eye increased (each P < 0.05) and that of patients with minor symptoms such as olfactory disturbances, cough, sore throat, and fatigue also increased (all P < 0.01) in the 2010s.ConclusionsAllergen reactivity and type and symptom severity in Korean AR patients significantly varied between the 1990s and 2010s. Our results may therefore be helpful for patient counseling and management.