Characteristics of study population.

ObjectivesTo quantify and describe flare-ups of house dust mite allergic rhinitis (HDM-AR) which had occurred during the last 12 months in a population of adults and children candidate for Allergen ImmunoTherapy (AIT). Next, to identify associated clinical features.Materials and methodsThis was an observational, multicenter, cross-sectional study that included patients aged ≥ 5 years with HDM-AR eligible for AIT and without prior AIT for at least 12 months. Flare-ups were all period with impairment of quality of life (QoL) and requiring a change in their usual treatment. Data were collected using medical records and patient questionnaires. Variables associated with the occurrence of ≥ 2 AR flare-ups were identified.Results1,701 patients were included (average age: 23 years, 51.5% males, 30.4% children, 17.7% adolescents and 51.9% adults). Severe and persistent AR affected 70.9% of them and 53.7% showed polysensitization. Asthma was associated with AR in 34.4% and was well-controlled in 58.5%. The occurrence of at least one AR flare-up in the year was reported by 77.7%, with an annual rate in the whole population of 2.6 ± 3.9 and a duration of 14.1 ± 17.1 days. Deeply or moderately AR-related degraded QoL was experienced by 39.5% and 64.6%, respectively. The occurrence of ≥ 2 AR flare-ups was reported by 54.5% and was associated with polysensitization, AR intermittence and severity.ConclusionAR flare-ups are frequent and impair QoL in HDM-allergic patients, suggesting that it could be considered as therapeutic targets.