Several types of mites are associated with cases of skin dermatitis in humans. The tropical rat
mite, Ornithonyssus bacoti, is one of the most commonly encountered species. The tropical fowl mite,
Ornithonyssus bursa, and northern fowl mite, Ornithonyssus sylviarum, both associated with domestic
or wild birds, can also be found in homes. The tropical rat mite is a parasite of rats and inhabit the area
in and around the rat’s nesting area. Although none of these species are truly parasitic on humans or
pets, they will readily bite humans. Some people are unaffected by the bites while others will
experience itching and dermatitis. The bite is normally pimple sized that itches for up to a week or so.
The bite mark may last as long as three weeks. The bites can be randomly found on the body but often
are found under areas where clothes constrict the body or areas such as under armpits and breasts.
Scratching may lead to secondary bacterial infections. Fortunately rat mites do not vector disease.
Rat mites are very small, approximately the size of a period.

The sheet includes photos of spiny rat mites and tropical rat mites, and of bites on a woman from a tropical rat mite. (Though these are in black and white, they are nevertheless helpful.)

You can click here to download a PDF and read the rest.

Oregon State provides an overview in “Mites that Bite” to various biting (and other) mites and ticks here (click to load PDF).

Texas A&M Cooperative Extension notes that the most important thing to do when faced with biting mites is to seek possible bird or rodent sources. Identifying the mite that’s biting you is crucial.

Identification and detection are not simple, since mites are so small.  You really need a professional to detect, identify and get rid of mites found in the home.