Hypersensitivity to house dust mites (HDM) exists in Atopic Dermatitis (AD) patients. HDM is an important aeroallergen, but its role in AD is not clearly understood. We investigated the presence of HDM on the skin, clothes and bedding of AD patients.

Skin surface samples were collected by sticky tape and examined by light microscopy. Dust samples from clothes and bedding were collected using a vacuum cleaner. The patients were examined before and after implementation of HDM environmental control measures including three skin treatments with an acaricide cream (5% permethrin).

Mites were found on the skin of 8 out of 9 patients. Two patients were infested with Dermatophagoides species, and the others with the hypopus stage of astigmatid mites. Two control patients were infested with Dermatophagoides pteronyssinus and Dermatophagoides farinae. Mites were found in all 43 dust samples. Mite number varied between 160 and 2,300 in clothing and between 30 and 5,100 per gram dust in bedding. After implementation of mite control measures including acaricide skin treatment, the mean HDM score in bedding and clothing decreased from 43.6 ± 63.6 to 11.5 ± 11.2, and from 12.3 ± 12.5 to 7.7 ± 6.4 respectively; the mean clinical SCORAD decreased from 54.0 ± 20.4 to 21.7 ± 13.2 (p=0.001).

The HDM presence on the skin, clothing and bedding of AD patients may contribute to itching and transepidermal sensitization to HDM. The presence of mites from all developmental stages on human skin warrants further investigation of HDM-biology and human-mite relationship. Skin treatment with acaricide and HDM control measures can decrease AD symptoms.