Rodent mite dermatitis (also known as rat mite dermatitis) is an often unrecognized ectoparasitosis occurring after human contact with

haematophagous Hematophagy (sometimes spelled haematophagy or hematophagia) is the practice by certain animals of feeding on blood (from the Greek words αἷμα ' "blood" and φαγεῖν ' "to eat"). Since blood is a fluid tissue rich in nutritious p ...

mite Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear e ...

s that infest

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

s, such as

house mice The house mouse (''Mus musculus'') is a small mammal of the order Rodentia, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus''. Although ...

, rats and

hamster Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera.Fox, Sue. 2006. ''Hamsters''. T.F.H. Publications Inc. They have become established as popular small pets. The ...

s. The condition is associated with the tropical rat mite (''

Ornithonyssus bacoti ''Ornithonyssus bacoti'' (also known as the tropical rat mite) is a hematophagous parasite. It feeds on blood and serum from many hosts. ''O. bacoti'' can be found and cause disease on rats and wild rodents most commonly, but also small mammals ...

''), spiny rat mite (''Laelaps echidnina'') and

house mouse The house mouse (''Mus musculus'') is a small mammal of the order Rodentia, characteristically having a pointed snout, large rounded ears, and a long and almost hairless tail. It is one of the most abundant species of the genus ''Mus''. Although ...

mite (''

Liponyssoides sanguineus ''Liponyssoides sanguineus'' is a species of mite that infests the house mouse (''Mus musculus''). It can transmit human disease, is associated with causing rodent mite dermatitis in humans and is noted for carrying '' Rickettsia akari'', which c ...

'') which opportunistically feed on humans. Rodent mites are capable of surviving for long periods without feeding and travelling long distances when seeking hosts. Cases have been reported in homes, libraries, hospitals and care homes. A similar condition, known as

gamasoidosis Gamasoidosis, or dermanyssosis, is a frequently unrecognized ectoparasitosis and source of growing concern in human medicine, occurring after contact with avian mites which infest canaries, sparrows, starlings, pigeons and poultry and caused ...

, is caused by avian mites.

Symptoms and signs

Rodent mite bites leave multiple groups or individual small itchy papules (around 1–2 mm in diameter) on the skin (papular urticaria). These are found mostly "on the upper extremities, neck, upper trunk and face".

Diagnosis

Diagnosis requires species identification of the parasite, which will be likely to be found in the environment of its host rather than on the hosts’ skin. Rodent mites are very small, for ''O. bacoti'' "female mites reach a size between 0.75 and 1.40 mm, males are a little smaller".

Treatment

The original rodent host of the mites must be located and eradicated, and their nests removed. Steps should also be taken to prevent future infestations, such as by blocking the rodents means of entry into the building. The patient's environment should then be treated, using both non-residual and residual insecticides, mites crawling in the open can be removed by vacuuming or with a cloth moistened with alcohol. Bites can be treated with

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

s and

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

s, to relieve the associated itching and allergic reactions.

Epidemiology

''L. sanguineus'' has been implicated in the spread of

Rickettsialpox Rickettsialpox is a mite-borne infectious illness caused by bacteria of the genus ''Rickettsia'' ('' Rickettsia akari''). Physician Robert Huebner and self-trained entomologist Charles Pomerantz played major roles in identifying the cause of t ...

References

{{Mite-related diseases and infestations Dermatitis Parasitic infestations, stings, and bites of the skin Rodent-carried diseases

Symptoms and signs

Diagnosis

Treatment

Epidemiology

See also

References