Cluster analysis of indoor environmental factors associated with symptoms of mite allergy

The clinical efficacy of controlling environmental allergens as a component of allergic asthma treatment remains controversial. Multifaceted allergen reductions appeared to be the most efficient methods. However, they require home visits with indoor technicians. To examine the characteristics of indoor environments that might be related to symptoms of children and adult patients with mite allergic rhinitis and/or asthma. We included 315 patients allergic to house dust mites with rhinitis and/or asthma who had been visited at home by 2 medical indoor environment counselors (MIECs) from the Strasbourg University Hospital between January 2007 and June 2015. In a cluster analysis, we analyzed 42 characteristics of respiratory symptoms, dwelling characteristics, and indoor pollutants in this population. Three clusters were defined among the patients. Cluster 1 included 55 patients, all with rhinitis, 32% with asthma, and all living in an urban area. Clusters 2 and 3 included 86 and 174 patients, respectively. The important factors in these 2 clusters were asthma incidence and exposure to different indoor pollutants, such as indoor perfumes, cleaning products, and tobacco smoke. Our results underlined the variability of indoor environments and the importance of MIEC home visits to investigate individual patient environments and propose an appropriate avoidance management plan. Our results showed that sensitization to mite and exposure to indoor chemical pollutants were associated with severe asthma.