A Case Study of Itching Dermatitis Caused by Cheyletus fortis (Oudemans, 1904) (Acarina : Cheyletidae) Found in Okayama Prefecture, Japan
Itching eruptions in a woman caused by cheyletid mites probably from new Tatami-mats (rice straw mat) is reported. On August 1987, the scattered itching eruptions were found on skin surface of the lower extremities of a 50-year-old housewife living in Kurashiki City, Okayama Prefecture, Japan. The patient has exclusively been resided in a Tatami-mat room which was recently annexed to a country-style frame house. A large number of mites were found on the Tatami-mat surfaces of the room right after she noticed the presence of itching eruptions on her legs. The number of mites appeared to be increased. On acarological observations the mite is identified as Cheyletus fortis (Oudemans, 1904) based on morphological analyses of gnathosoma, pedipalps, comb-like setae, thumb-claws, dorsal and dorso-marginal setae and other characteristics. The skin lesions of the patient were completely healed within about two weeks after the mites disappeared entirely from Tatami-mat surfaces by repeated control with a pertinent acaricide.