A human case of otoacariasis involving a histiostomatid mite (Acari: Histiostomatidae).

A 31-year-old Saudi man was seen at an ear, nose, and throat clinic at Riyadh, Saudi Arabia, with bilateral itching in the external auditory canal. On otoscopic examination, the skin lining the ear canal was thickened with whitish sheets of sloughed cells and thick discharge. Large numbers of mites of an undescribed species closely related to members of the genus Loxanoetus (Histiostomatidae) were present. The patient underwent successive washings of the ear canal with saline and 70% ethanol at intervals of 2-3 months and was treated with antibiotics. Treatment with Eurax (crotamiton) ear drops for one week cleared the mite infestation. This represents the first reported case of human otoacariasis involving a histiostomatid mite. Based on the known biology of histiostomatid mites and the associated hosts of Loxanoetus and related genera, there is reason to speculate that the patient acquired the infestation while swimming in a lake or pond where this mite was present.