What are itch mites? 

Itch mites are microscopic insect-like creatures that cannot be seen by the naked eye. There are several different kinds of itch mites.

One type, the oak leaf gall mite, is believed to be responsible for outbreaks of human bites in 2004 in Kansas, Missouri, Nebraska and Texas. The mite feeds on the larvae of a small fly (midge) which forms a brown and crusty shell on the edge of an oak leaf (known as a gall).