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 ...

mite Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as eac ...

s that infest

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

s, such as house mice,

rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...

s and

hamster Hamsters are rodents (order Rodentia) belonging to the subfamily Cricetinae, which contains 19 species classified in seven genera. They have become established as popular small pets. The best-known species of hamster is the golden or Syrian ...

s. The condition is associated with the tropical rat mite ('' Ornithonyssus bacoti''), spiny rat mite ('' Laelaps echidnina'') and

house mouse The house mouse (''Mus musculus'') is a small mammal of the rodent family Muridae, 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''. A ...

mite ('' Liponyssoides sanguineus'') 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, also known as dermanyssosis, is a frequently unrecognized form of zoonotic dermatitis, following human infestation with avian mites of the genera ''Dermanyssus'' or ''Ornithonyssus''. It is characterized by pruritic erythematous pa ...

, 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 host's 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 provides ...

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 invo ...

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 ...

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