Occurrence of mites and fungi in the homes of patients with allergic manifestations

Abstract

This survey was carried out to evaluate mites and moulds concentrations in the homes of patients with allergic manifestations and positive skin-test for mites and/or fungi. The home environments of 277 patients were evaluated by questionnaire, by sampling of airborne fungal spores and by determining the occurrence of mites and moulds in dust samples. Among the 277 patients examined, 83% reacted positively to house dust mites. The fungal allergen most frequently responsible for skin positivity was Alternaria tenuis. The prevalent airborne fungi were Cladosporium, Penicillium and Alternaria, followed by Aspergillus and Aureobasidium. The other genera were found in less than 50% of the homes. The presence of domestic mites in dust was documented in more than 85% of the homes sampled. The occurrence of fungi in dust was generally higher than in the air. The most common genera recovered were Penicillium, Candida, Aspergillus, Aureobasidium, Alternaria and Cladosporium. The homes investigated were divided into two groups, damp and dry, on the basis of the reported presence of wet or damp spots on inside surfaces and moulds growing inside the home. Our results showed that the concentration of mites and moulds in dust was significantly higher (p < 0.01) in damp homes as compared to dry ones. In general, a good agreement between skin positivity and presence of the same allergens in patients' home environment was observed for mites and, among fungi, for Alternaria, Cladosporium and Aspergillus. Our results seem to confirm that the study of mycoaeroflora and the quantification of mites and moulds in dust samples of allergic patients' homes could lead to more precise diagnoses and therefore to better prophylactic and therapeutic programs for each individual patient.