Exposure to Mites, Sensitisation and Allergy to Mites in Moisture Damaged Buildings

Abstract

We assessed the mite exposure of patients in the Skin and Allergy Hospital by collecting samples of settled dust from their workplaces and homes. Mites were counted and identified microscopically. Mites were found in 26% of the samples. Three samples (3%) contained more than 100 mites per gram dust and another sample (1%) had more than 500 mites per gram dust, the suggested limits for mite sensitisation and at which acute allergic symptoms can be expected, respectively. Mites were a more common finding from water damaged houses and workplaces with visible mould but they also existed in large numbers in buildings with no reported indoor air quality problems. Dust mites ( Pyroglyphidae) were the most abundant species. However, storage mites were also frequently found. Patients reported a high prevalence of respiratory symptoms, especially nose and eye irritation which may partly be due to sensitisation especially to storage mites. Although mites are commonly found in workplaces and homes they are seldom present in high concentrations. Mite sensitisation and especially a positive reaction to storage mites in skin prick tests may be an indication of a moisture problem in the domestic or work environments.