Cheyletiellosis (Walking Dandruff Mite) in Dogs

Cheyletiella is a relatively uncommon mite, although it is considered highly contagious. It is more prevalent where fleas are not. It lives on the surface of the host's skin and does not burrow. It derives it’s common name because when the large mite appears to be dandruff “walking.” Cheyletiella can be seen with the naked eye or a magnifying glass. The King Charles Spaniel, American Cocker Spaniel as well as Boxer dogs seem to be most susceptible to this mite although any dog that is groomed regularly, attends doggie daycare or frequents a place with many other dogs could be at risk.

Cheyletiellosis is a type of dermatitis caused by the mite known as, the walking dandruff mite. Cheyletiella can affect dogs, cats, and humans.  Although it is possible to contract from your pet, humans are not the preferred host. The walking dandruff mite can not complete their cycle on humans. If you treat your dog, your symptoms will clear without specific treatment within three weeks.

Dogs carrying the walking dandruff mite can be asymptomatic but still transmit to other members of the household. The most tell-tale symptom for cheyletiellosis in dogs is large flakes usually appearing on the dorsum (or upper back.) Symptoms can vary, especially between hosts. At times red lesions are present. Lesions are more common on humans and usually appear on the arms, neck, chest, and abdomen. Other symptoms for your pet include: 

• Excessive itching
• Excessive grooming
• Face rubbing
• Sneezing

Types

Cheyletiella yasguri is the species that generally affect dogs. Cheyletiella blakei is more prevalent in cats. Other species can affect rabbits and possibly other wildlife. All members of the genus have a similar “shield” like shape to their body. Cheyletiella yasguri can be identified from other species by the shape of its legs (although species identification is often made by host association.)

Cheyletiellosis is caused by an infestation of the walking dandruff mite. Cheyletiellosis is more common in warm and tropical areas. When an infestation is present it is often in a  young, old or unwell host. Cheyletiella mites are transmitted from direct contact with an infected host. Many healthy and robust animals may show no symptoms at all. Your dog may be suffering from cheyletiellosis if he was recently at a:

• Grooming salon
• Kennel or doggie daycare facility
• Breeding facility
• Shelter or rescue group
• Dog park

Puppies are most susceptible to contract Cheyletiella yasguri from their mother in the first few weeks of their life.

Because of the relative rarity of Cheyletiella yasguri it is considered to be underdiagnosed. It can commonly be mistaken for a flea allergy. If the dog has been groomed recently the prevalence of the mites will be less and harder to spot. One note is that walking dandruff mite infestations are nonseasonal. Ironically, because of their large size the walking dandruff mite can be diagnosed with the naked eye, a simple magnifying glass or a microscope on a low setting. Under a microscope their hooklike mouths are visible. A skin scraping will assist your veterinarian with the diagnosis. Round fecal matter will often be present. The eggs attach to the hair shaft like lice. Other methods include using a flea comb or what is referred to as the “Scotch tape method”, in which the mites are rendered immobile and are easy to spot with a loupe.

Your veterinarian will need to assess the health and condition of your pet to determine treatment. Often clipping of long hair is suggested. As little as four or many as eight weekly baths in pyrethrin (an insecticide), shampoo is a common treatment. Ivermectin is an internal medication sometimes prescribed. Ivermectin comes with a set of cautions. It should not be used on herding dogs or crosses of any kind. It is generally avoided in older dogs as well. All dogs prescribed Ivermectin should first be determined to be heartworm negative. It is suggested to also treat the environment to prevent reinfestation. Cheyletiella yasguri is an obligate parasite and can not live without a host for more than ten days. Home flea treatments have little effect. General housekeeping (washing of bedding) seems to be the best remedy. Insecticidal spray in kennels helps to minimize risk. All pets that come in contact with one another should be treated regardless of whether or not symptoms are present.

Reinfestation is possible from non-symptomatic pets in the household. That is why it is important that all pets are treated. While reinfestation is possible from the environment, it is less likely as  the mites can only live off the host for up to ten days. Still, it is important to treat the environment as well. With proper management, you can expect a full recovery in three weeks.