Skin Mite Dermatitis in Dogs

Cheyletiellosis in Dogs
The Cheyletiella mite is a highly contagious, zoonotic skin parasite that feeds on the the keratin layer of the skin - the outer layer - and on tissue fluid of the top layer. An infestation of the Cheyletiella mite is medically referred to as cheyletiellosis. This parasitic skin condition is similar to a flea infestation, and is treated with the same products, and with the same environmental methods used for exterminating fleas. Prevalence varies by geographic region largely because common flea-control insecticides control it. The Cheyletiella mite can live off of other hosts and is transmittable to humans.

A Cheyletiella infestation is also referred to as "walking dandruff," because of the way the mite maneuvers around beneath the keratin layer, pushing up scales of skin so that they seem to be moving, and leaving a dusty surface of skin scales on the surface of the hair. The mites generally cause moderate irritation, but in young animals this infestation can be more severe when coupled with skin abrasions, and an increased risk of infection due to an immature immune system.

The condition or disease described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects cats, please visit this page in the PetMD health library.

Symptoms and Types
Alopecia
Excessive scratching
Visible scaling of the skin
Dusting of skin flakes (dandruff) on the surface of the hair
Lesions on the back
Underlying skin irritation (may be minimal)
Small yellow skin mite may be visible on close inspection
Causes
Frequent contact with other animals
Recent stay in animal shelter, breeding establishment, grooming establishments, kennel
May be picked up in an environment apparently lacking animal presence
Re-infestation from improperly decontaminated bedding or housing
Diagnosis
Other diseases that have similar symptoms are dandruff, flea-allergic skin irritation, infestation by mites other than Cheyletiella, allergy due to food sensitivity, diabetes, and skin allergies that are particular to your dog. Even so, it is general practice to test for cheyletiellosis when any of the obvious symptoms are present.

Your veterinarian will take samples of your dog's skin, and debris from the top layer of the skin and hair for examination. Even if the mites are not readily visible by looking at the dog, they are large enough to be discovered with a simple magnifying lens. The process is straightforward: the mites are easily collected using a piece of tape, or by a skin scraping. They can also be found in a stool sample, since they are frequently ingested during grooming and passed through the digestive tract undigested. If Cheyletiella mites cannot be identified for certain, your veterinarian may want to test your dog's response to insecticides.

Treatment
When a dog displays cheyletiellosis, all animals in the household must be treated, as the mite can live for up to ten days away from a host. It is also important to thoroughly clean bedding, kennels, and rugs, so that the mite does not re-infect your dog, or infect other pets. Pets must then be bathed six to eight times a week to remove skin scales. In addition to insecticide and lime-sulfur rinses, your veterinarian may also prescribe oral medications. If the dog has a long coat, it must be clipped to a short length.

Living and Management
If you have been in contact with an infected animal, or your pet is infested with the Cheyletiella mite, you may develop a reaction, such as itching, small red bumps, or minor lesions, but the condition will clear on its own through the normal course of bathing yourself. It is best if you disinfecting your dog and its living environment, as well as disinfect and/or discard its combs, brushes, and other grooming equipment.

If the treatment regimen does not work, your veterinarian will look for other causes for the symptoms. Re-infestation may come from another carrier or from the presence of an unidentified source for the mites, such as untreated bedding.