To the Editor.—
Lyponyssus ( =Bdellonyssus) bacoti (Hirst, 1913), the rat mite, may infest man as a secondary host. Such an infestation results in a chronic dermatitis. Often, as when several individuals are exposed to the same source of mites, it is a group disease.1-3 Recently we saw a young boy with rat-mite dermatitis. Investigation revealed that all members of his household were similarly afflicted and that their tenement contained numerous rats and rat mites.
Report of Case.—
The patient was an 8-year old boy of Puerto Rican background. When first seen, he had had a widespread episodic pruritic eruption for about three months. Skin changes and itching were worse on the exposed areas, particularly along the flexural aspects of the arms and legs. There was considerable day-to-day fluctuation in the intensity of his disease. He had been thought to have eczema, but treatment with lubrication and topical steroids for