CHEYLETIELLA  (walking dandruff)

Cheyletiella - parasitic mite on dogsDescription
Cheyletiella are parasitic mites that infest and cause skin disease in several species including cats, dogs and rabbits. It is a worldwide disease. The mites can be transmitted to humans and cause an itchy rash, so they are a potential zoonosis.
[The mites have specialized mouth parts allowing them to puncture the dog's epithelial layer and feed on body fluids. The normal reaction to this insult to the epithelial layer is a mild dermatitis accompanied by local redness. The resulting itchiness of the dermatitis coupled with the irritation of possible secondary skin infections often lead to excessive scratching or biting which in turn may result in hair loss in affected areas. Often starting in the rump area, the infestation is capable of spreading to eventually involve most body parts.]

There are 3 common species of Cheyletiella mite: 

  • Cheyletiella yasguri - most commonly found on dogs 

  • Cheyletiella blakei - most commonly found on cats

  • Cheyletiella parasitovorax - most commonly found on rabbits

  • All species of mite can be transmitted to other animals or to humans

The mites are large (385 mm) live on the skin surface and their eggs are attached to hair shafts. The mites lifecycle lasts 21-35 days on the host animal, but the adults are reported to be able to survive off the host for 2-14 days, so infestation can be contracted from the environment as well as by direct contact.

Breed Occurrence
There is no breed predisposition.

These mites cause a variety of clinical signs including the following: 

  • Scale (scurf or dandruff) formation.

  • Large numbers of small white Cheyletiella mites moving about on the surface of the skin is often called "walking dandruff" !

  • Itchiness (pruritus) - usually mild

  • Inflammation of the skin (redness)

  • Crusts

  • Small swellings/spots (papules)

Failure to cure Cheyletiella infestation can be due to them living intranasally 

Diagnosis can be difficult and it is made by taking:

  • Skin scrapings

  • Samples on sticky tape

  • Combings

and finding mites or their eggs under a microscope. Eggs can also be found in faecal samples. The mites have 4 pairs of legs with combs (not claws) and accessory mouthparts with terminal hooks. 

A variety of antiparasitic preparations can be used to treat Cheyletiella mites, including:

  • Selenium sulphide-based shampoos applied once a week for up to 5 weeks

  • Dips in pyrethrin - following manufacturers instructions - dogs, cats and rabbits

  • Dips in lime sulphur - following manufacturers instructions, usually weekly for 3-4 weeks- dogs, cats and rabbits

  • Dips in Amitraz - 3 dips at 2 week intervals - dogs only

  • Injections of ivermectin (0.2-0.3g/kg for up to 3 doses given at 2 week intervals) in breeds of dog (only) in which it is not contraindicated. Some authors do not recommend the use of Ivermectin in dogs at all, and it should NOT be used in Beagles, Collies, Shelties or Collie-crosses as clinical signs of toxicity have been reported to occur at the following doses :

  • Beagles - 2.5 - 40mg/kg

  • Collies - 0.1 - 0.2 mg/kg

The environment should be treated by using a vacuum and use of an environmental flea control spray


Long term problems

* You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet. 

Information provided by Provet for educational purposes only. 
Web Site


Cheyletiellosis is an itchy, scaling skin disease of dogs caused by infestation with Cheyletiella mites. It is often called walking dandruff because when you examine an infested dog, you may see that the “dandruff” is moving. The movement is actually caused by the mites moving around under the scales. Although the mites inhabit the entire body, the scaling and itching often seem worse over the back.

Puppies seem to be more susceptible than older animals, but infestation of adults is sometimes seen. The mite is transmitted by close contact with infested animals. Since the mite can live for a few days off the host, it is also possible to become infected through environmental contamination. Poor sanitation and nutrition and overcrowding can lead to infestation. Thus, it is likely for puppies from puppy mills to show up in pet stores with this problem. 

The discomfort of itching and the lesions the animal can cause to himself by scratching is directly related to the impact of this disease on the dog.

What to Watch For:

  • Itchiness

  • Flaky, scaly hair coat


A medical history may reveal a scaly, itchy skin problem on one or more of the animals in the home, often after a recent addition of a new pet. These mites can temporarily infest people, so you may experience an itchy rash on arms, belly, back and chest. 

Your veterinarian will do a physical exam, which will probably reveal the characteristic scaly skin along the dog’s back. However, not all animals show this distribution of lesions. These mites are large compared to other mites and in cases of heavy infestation, you can see them on the skin with a magnifying glass.

Other diagnostic tests may include:

  • Flea comb. Combing with a flea comb is probably the most reliable method of diagnosis. The dog should be thoroughly combed all over the body and the scale that is collected on the comb should be viewed under a microscope. The scale may also be placed on a dark background and observed. These mites appear as white specks that move, hence the name “walking dandruff” mites.

  • Skin scrapings. Microscopic evaluation of skin is less accurate than flea combing in light infestation because only a small area of skin is evaluated. Skin scrapings are often done to rule out other itchy skin diseases like scabies, and the mite may be picked up in the process. 

  • Acetate tape. Impressions of the skin with clear acetate tape can pick up mites, which can then be seen when the tape is placed on a drop of mineral oil on a slide and viewed under a microscope. This method also has the disadvantage of sampling only a small area.

  • In cases where mites cannot be found, but a parasite is suspected, your veterinarian may elect to treat for the disease and look for a response to the treatment.


Although commonly used flea sprays, shampoos and powders may give temporary relief, more aggressive treatment is needed for long term success of walking dandruff mites.

Treatment includes:

  • Ivermectin is an effective treatment for Cheyletiellosis. It may be given by subcutaneous injection or orally. ** However, Ivermectin is toxic in herding breeds such as Collies and Shetland Sheepdogs. This drug is usually used every 1 to 2 weeks for at least 4 weeks.
    [Some dog breeds (Collies, Shetland Sheepdogs, Old English Sheepdogs, Australian Collies, and their crosses) seem to have greater penetration of Ivermectin through the blood-brain barrier. The critical point seems to be 120-150 µg/kg, at which transient, nonfatal clinical signs (mydriasis, ataxia, tremors) are seen. At higher doses, collapse, coma, and respiratory collapse may develop. Similar idiosyncratic reactions may develop in any breed, so a gradually increasing dose (daily progression of 50, 100, 150, 200, then 300 µg/kg) should be given to identify susceptible individuals. Administration should be stopped if any side effects are seen. One cat treated with 4 mg of the oral paste (~70 mg/kg) showed ataxia, blindness, tremors, and mydriasis, with retinal atrophy in one eye 10 hr later.]

  • Selamectin is a topical drug that is applied to the skin of dogs between the shoulder blades. This drug shows promise in treating Cheyletiellosis. It is applied monthly for at least two months. 

  • Lime sulfur dips are effective, although clipping of the hair coat may be necessary in medium and longhaired breeds to get the best results. Dips may need to be done weekly for 6 to 8 weeks.

  • Amitraz dips are also effective.

Whatever treatment is selected, it is important to treat all animals in the household.

Home Care and Prevention

Treatment of the home environment may be necessary to prevent reinfestation. Wash all bedding and discard brushes and combs. Vacuum carpets and upholstery thoroughly and repeatedly and spray the house with a flea premise spray.

Although it is difficult to prevent infestation by the walking dandruff mite, you can take some steps to lower exposure. You should avoid the dog while he is infested since the mites are highly contagious. 

Be sure to have any new animals evaluated by a veterinarian before admitting them to your home. Cheyletiellosis can be contagious to people so anyone handling the pet should thoroughly wash their hands and use appropriate caution.


Cheyletiella blakei infests cats, C yasguri infests dogs, and C parasitovorax infests rabbits, although cross-infestations are possible. 

This disease is very contagious, especially in animal communities. Human infestation is frequent. Mite infestations are rare in flea endemic areas, probably due to the regular use of insecticides. These mites have 4 pairs of legs and prominent hook-like mouthparts. They live on the surface of the epidermis, and their entire life cycle (3 wk) is spent on the host. Clinical disease is characterized by scaling, a dorsal distribution, and pruritus, which varies from none to severe. Cats can develop dorsal crusting or generalized miliary dermatitis. Asymptomatic carriers may exist. The mites and eggs may not be easy to find, especially in animals that are bathed often. Acetate tape preparations, superficial skin scrapings, and flea combing can be used to make the diagnosis. Weekly dippings with pyrethrins or lime-sulfur for 6-8 wk are necessary to eradicate the mites. Fipronil and Ivermectin are effective, but non-approved, treatments. The environment should also be treated with a good acaricide, especially in animal communities (eg, breeding colonies, kennels), given the fact that adults may survive off the host for several days or even weeks.


A Fish a Day Helps Keep Dandruff Away

We are all aware of the danger of having too much fat in our diets. Obesity is a major health concerns for our pets and us. But did you know that by increasing the daily intake of essential fatty acids in our pet's diets, that we may be able to correct certain medical conditions? 

Essential fatty acids are nutrients that must be obtained from our diets because the body is unable to manufacture them. The essential fatty acid that has received the most notoriety is Omega 3. This type of fatty acid is especially abundant in cold-water fish. Omega 6 fatty acids are also needed and can be found in animal tissue and plants.

Essential fatty acids are nutrients that must be obtained from our diets because the body is unable to manufacture them.

Studies that have shown the effectiveness of fish oils have been done mostly in humans rather than pets. The benefit that our pets will experience is expected to mimic that seen in their owners. 

Fish oils have been proven to improve the skin and coat of dogs that suffer from the allergic skin disease known as atopy. Atopy is the dog's equivalent to hay fever. Omega 3 fatty acids have also improved conditions ranging from cancer to inflammatory bowel disease. Cats are also aided by the addition of these fatty acids to their daily rations. 

Just like any supplement, care must be taken not to overdo a good thing. If your pet is taking certain anti-coagulants or is on high doses of vitamin E or ginkgo biloba, or if your pet is a diabetic, be sure to ask your veterinarian if this supplement should be taken by your pet. 

Dog & Cat Dandruff and .... Pet Shampoos 

The last thing you expect from your furry little friend is a blizzard of flaky skin. Dog dandruff, cat dandruff - what should a caring pet owner do???

"Pet dandruff looks like a really bad case of people dandruff - you can easily see it with most animals," says Nancy Scanlan, D.V.M., a veterinarian in private practice in California.

While occasionally dog dandruff and cat dandruff can indicate a serious health problem, like allergies, parasites, or skin infections, more often it occurs when skin cells naturally proliferate - they form, die and then flake off - at an accelerated rate.

Scott Weldy, D.V.M. says, "Since pet dandruff is a sign of flaky skin, giving your pet regular baths will help wash the flakes away before they accumulate. Bathing your pet once a month in winter and twice a month in summer may clear up the problem for good."

  • To bathe your pet, use warm water, Not hot water.

  • Use a mild shampoo and massage it well into your pet's skin.

  • Then rinse thoroughly and dry your pet well.

  • Don't use medicated shampoos made for humans because they can be harmful for pets.

  • Check the label carefully! Products that may be safe for dogs, may not necessarily be safe for cats.

  • To prevent making dandruff worse, avoid using shampoos that include an insecticide.

Most flea shampoos are very drying to the skin, thus creating more dandruff problems.

Regular brushing and grooming your pet will help distribute natural oils evenly over dry skin, which will help keep dandruff down. 

Choose a brush that's not too harsh. You can tell by rubbing the brush against the back of your hand to see if it will hurt. Something you would use on your own head will be excellent for your pet.

"If you've tried shampoos, regular brushing and new foods and it still looks like winter on your pet's coat, you're probably going to need professional help," says Jan A. Hall, D.V.M.

"While dandruff is usually nothing more than flaky skin, in some cases it can indicate serious problems. Warning signs to watch for, besides the flakes, include scabs, crusting or itching."

"Problems with the skin can be an indication of internal disease. After a month or so, if there is no improvement, you should take your pet to the vet."

According to Mollyann Holland, D.V.M., "Sometimes we'll see dandruff when animals aren't getting enough fat in their diets. Giving your pet fish oil supplements will help improve the metabolism of fats in skin tissue. Some generic and supermarket brand foods do not provide the full range of vitamins and minerals your pet needs to maintain a healthy skin. Many pets have been taken off generic foods and put on a high quality food and the cases of dandruff have disappeared."

* In cases of eczema or dandruff type conditions where the animal has been given the proper Omega 3 fatty acids and vitamin E but the trouble still persists, this can be indicative of liver congestion.

* Several successful exhibitors I know use a horse product called SUPER 14, made by Farnham. It contains 14% fatty acids, vitamins E & B6 to make skin healthy, coat sleek & glossy. You should use it only until the coat is repaired and in healthy condition.


Scaling Skin (Exfoliative Dermatoses) 

What are exfoliative dermatoses? 
Exfoliative dermatoses are a group of skin disorders characterized by excessive or abnormal shedding of cells from the surface of the skin. This condition results from an increase in skin cell production, an increase in the shedding rate, or a decrease in the ability of skin cells to stick to each other. These skin cells, shed individually or in sheets, can be found throughout the animal's hair coat. The skin of an affected animal often becomes scaly in appearance. Exfoliative dermatoses may be seen in dogs or cats. Certain breeds of dogs tend to be at higher risk for developing exfoliative dermatoses than other breeds. 

What causes exfoliative dermatoses? 

Exfoliative dermatoses are a group of skin disorders with many causes. The term, exfoliative dermatoses, describes the scaling skin that is common to these disorders; it is not a diagnosis. Some primary causes of exfoliative dermatoses include oily skin (seborrhea), vitamin or nutritional deficiency, and inherited (genetically acquired) skin defects. Exfoliative dermatoses can be a sign of bacterial, fungal or parasitic skin infection; allergic skin disease; or hormonal imbalances. 

What are the signs of exfoliative dermatoses? 
Exfoliative dermatoses have the clinical sign of scaling skin in common. The animal often has a history of itchiness, excessive dandruff, and foul-smelling skin. Upon physical examination, the animal's coat may appear dry or greasy with abnormal amounts of scale found throughout the hair coat or on the skin. Debris may be stuck around the hair shafts and areas of hair loss may be seen. The animal may have additional signs depending on the underlying cause. The animal may have a secondary bacterial skin infection if the skin is damaged severely. 

How are exfoliative dermatoses diagnosed? 
Exfoliative dermatoses are diagnosed by medical history and physical examination. The veterinarian wants to diagnose the underlying cause to prescribe appropriate treatment. The animal's breed, age, and history are important in determining the underlying cause of exfoliative dermatoses. Laboratory tests (such as complete blood counts [CBCs], blood chemistries, and urinalysis) may be performed to evaluate the pet's general health status and to identify possible underlying causes of the scaling skin. A diagnostic skin work up may be performed. Tests may include skin scrapings, bacterial or fungal cultures, or skin biopsy (surgical removal and microscopic examination of skin). Specific hormonal tests may be performed if thyroid gland or adrenal gland problems are suspected. If allergies are likely, the veterinarian may perform intradermal skin tests or blood tests to identify likely substances (allergens) to which the animal is allergic. 

How are exfoliative dermatoses treated? 
The treatment for exfoliative dermatoses is directed at the scaling skin itself as well as the underlying cause. Exfoliative dermatoses can be treated with medications applied directly to the skin (topical). The animal is bathed with specialized shampoos and moisturizers, according to your veterinarian's directions. Whereas shampoos remove scales, they also potentially can cause excessive dryness and discomfort. Therefore, moisturizers are used to restore moisture or re-hydrate the skin. Antibiotics are required if bacterial skin infection is present. Additional treatment may be needed to treat the underlying cause of exfoliative dermatoses. Recheck examinations should be scheduled at regular intervals to monitor the response to treatment. 

What is the prognosis for animals with exfoliative dermatoses? 
The prognosis (outcome) for animals with exfoliative dermatoses can range from guarded to good, depending on the underlying cause. Treatment of exfoliative dermatoses often is required for the animal's entire life, since these conditions can recur or worsen. 

Vet Med Center
Web Page



Main Categories