Acariasis

Acariasis

Key Points

Normal hosts are birds, occasionally other animals are infested

Can produce intensely itchy rash, manifest as papules (small bumps), vesicles (small blisters), or dermatitis(eczema-like rash)

Not well recognized; often overlooked

Cutaneous manifestations of infestation with avian(bird) mites in humans are often unrecognized, and may be more common than previously thought. Typical hosts include wild (e.g. sparrow, pigeon, starling, swallow, robin) and domestic (e.g. canary, chicken) birds, as well as occasionally small mammals, such as gerbils or mice. Bird mites are blood suckers (as opposed to scabies mites, which are burrowers) and often feed at night. Affected individuals may develop either widespread or localized pruritic papules, at times with a hemorrhagic center, vesicles, or eczematous dermatitis on exposed skin or intertriginous areas( areas where the skin folds on itself, e.g. underarms or groin).  Examples of reponsible mites include Ornithinyssus sylviarum and Dermanyssus gallinae.

Differential Diagnosis (Conditions with a similar appearance)

Quite broad, because of the range of clinical appearances in different patients. Not all exposed persons will develop a reaction to the mite bites.

Papular urticaria

Scabies

Infestation with body lice

Flea or other insect bite reactions

Dermatitis herpetiformis

Eczematous conditions

Diagnosis

Key Points

Intensely itchy, localized or generalized, eruption manifest as papules, vesicles, or eczema -like eruption of an adult or child. More than one member of the household may be affected. Rash usually unresponsive to prior attempts at therapy by the patient or physician.

Solicit a thorough history, with emphasis on possible sources of infestation, e.g. bird nests of eaves, windows, air conditioners, vents, attic, etc., or domestic pets, such as exotic birds, gerbils or mice.

The organisms are about 0.5 to 1 millimeter in length, barely visible to the naked eye. However, microscopic examination of cellophane tape stripping of affected skin may reveal the mites.

Veterinarians may be able to identify mite infestations of domestic pets.

Treatment

The source of the mites must be identified and removed in order to effect cure. Bird nests on and around domestic dwellings should be relocated, and pets (exotic birds and small mammals) should be examined and treated if necessary by a veterinarian. Pet cages and bedding can also act as resevoirs for mites, and should be thoroughly cleansed and disinfected. Until the diagnosis is made and the source of the mite infestation is addressed, treatment is aimed at relief of symptoms, such as through the use of topical counterirritants  (e.g.Sarna loton), topical corticosteroids, and oral antihistamines.