Cheyletiella mites live on the skin, causing irritation, dandruff, and itchiness. A distinguishing feature of this mite species are the large, claw-like mouthparts. These mites can be found quite commonly on cats, dogs, rabbits, and other species. Though humans are not a natural host for this parasite, Cheyletiella mites can happily live on humans for a while, causing an itchy rash.
What Is Cheyletiella?
Cheyletiella is a type of mite. The adults are about 0.385 millimeters long. They have eight legs and instead of claws, they have combs. The mites live on the skin's keratin surface and do not burrow into the skin. Cheyletiella has a 21-day life cycle on a host and cannot survive without a host for more than 10 days.
Infestation with Cheyletiella is also sometimes called "walking dandruff," since the movement of the mites among the flakes of skin tends to make it look like the dandruff is on the move. Medically speaking, infestation with Cheyletiella mites is called "cheyletiellosis." Sometimes the Cheyletiella mite is also called the "rabbit fur mite," but there are actually several species of Cheyletiella mites that tend to prefer different species of host. Though Cheyletiella mites generally live on the skin, there have been cases where they enter the nostrils and hang out in the nasal passages, too.
Identifying the Cheyletiella species involved is irrelevant, however, as the symptoms and treatment are identical for the different Cheyletiella species, and the mites sometimes cross over to other host species given the chance. They will also move onto people, though they don't complete their life cycle on people so human infestations are considered transient.
Symptoms of Cheyletiella in Cats
The symptoms of Cheyletiella vary among animals. Some pets will have no symptoms at all and others will have multiple symptoms. Any skin-related symptom will occur primarily on the animal's back. They may include:
- Flaky skin (dandruff)
- Scratching (itchiness)
- Reddened skin
- Small bumps on the skin
- Scabs on the skin
- Mild hair loss
- Sneezing and scratching at the face (if mites enter the nose)
Causes of Cheyletiella
The mites are often picked up from direct contact with another infested animal. They are common when a group of animals lives together, like in a pet store or farm. The mites and eggs can survive for a short time (days to weeks) in the environment so infestations can be picked up indirectly by contact with bedding, toys, or other objects carrying the mites.
Diagnosis of Cheyletiella
Though sometimes Cheyletiella mites can be seen moving about on the skin, in many cases they can be quite difficult to find. Scrapings of the skin or samples of dandruff caught on sticky tape or gathered by a fine comb can be examined for the presence of the mites or their eggs. Their eggs can also sometimes be found in fecal samples because they are swallowed during self-grooming behavior. None of these methods are foolproof. Since they are so hard to find, the mites may not be discovered even when they are present. It is particularly hard to identify them in cats.
Cheyletiella may be strongly suspected based on the signs and symptoms, so even if the mites can't be found, your vet may still recommend treating for Cheyletiella. Trial treatment is a good way to rule out Cheyletiella before moving on to investigate other causes of skin problems, which can be difficult to sort out.
Treatment and Prevention
There are several options for treating Cheyletiella and your vet will recommend a treatment appropriate for your pet and household situation. In addition to treating the pet, the household environment (floors, bedding, toys, etc.) must be treated as well. Your vet can offer advice on the appropriate treatment of the home environment. All pets in the home should be treated at the same time, as it is possible for them to carry Cheyletiella mites without showing symptoms. Treatment options include:
- Selamectin (brand name Revolution), a parasite preventative applied to the skin, is effective in treating Cheyletiella.
- Milbemycin (brand name Interceptor) is an oral parasite preventative that has also been used in cats to treat Cheyletiella.
- Ivermectin is an anti-mite medication that can be given orally or by injection. The doses required have caused adverse reactions in pets, as well as in occasionally sensitive individuals.
- Topical treatments such as sprays, shampoos, and dips can be effective against mites (e.g. pyrethrin-based products, lime-sulfur dips). It is very important to follow your vet's advice on which products to use for cats and for applying these products safely. These treatments are time-consuming and if mites take refuge in the nasal passages, topical treatments will not be as effective as the above medications, which are absorbed into the body.
Cheyletiella infestations on people are self-limiting since the mites won't reproduce on humans. Symptoms on people should resolve once mites are cleared from the household pets.