Rat mite dermatitis.

Infestation by the tropical rat mite (Ornithonyssus bacoti) is presented with bizarre symptoms that made an accurate diagnosis difficult. The physical characteristics, life cycle, habits, and epidemiology of the tropical rat mite are discussed, as are the rat and other hosts, the rash produced by the mite, differential diagnosis of the dermatitis, and the treatment of the dermatitis and control of the infestation.