Rhinitis and asthma co-morbidity in respiratory allergy due to house dust mite: results of an observational open controlled parallel group study in real-life setting.

Background: Some aspects of allergic progression still need to be addressed. To prevent the onset of the progression is not, at present, a very realistic aim, although therapeutic instruments are available to delay and, if possible, to stop it. We attempted to clarify these points in an observational open controlled three-parallel group study in a real-life setting.

Methods: 3838 patients with respiratory allergy due to house dust mite have been enrolled in this observational study. 2200 patients with rhinitis and/or intermittent or mild persistent asthma, poorly responsive to standard pharmacological therapy (SPT) were treated for three years with SPT associated or not with specific immunotherapy (SIT). Symptom medication scores, pulmonary function test (PFT) and methacholine (MCh) challenge were performed at the beginning and at the end of the study. 1638 pure rhinitics, responsive to SPT, enrolled as a control group, used self-medication (SM) on demand to assess the incidence of asthma in non-treated patients with standard therapeutic protocols.

Results: 694 patients have been treated with SPT+SIT, 1506 with SPT and 1638 with SM. Co-morbidity rhinitis-asthma incidence was higher in the SM group (an overall 69.27% including asthma and bronchial hyperreactivity). Persistent rhinitis proved more often to be associated with asthma than intermittent rhinitis. Likewise, the moderate-severe forms compared to the mild ones. The addition of SIT to SPT reduced the allergic progression in all patients.

Conclusions: In everyday clinical practice too, SIT proves its efficacy in the treatment of allergic march. Patients with moderate-severe persistent rhinitis appear as the ideal candidates for this therapy.