Young dogs with heavy “dandruff” over their necks and backs – especially if the flakes of dandruff move – should be suspected of being infested with Cheyletiella mites. They may or may not have any symptoms of itchiness.
The attending veterinarian may recommend a urinalysis and routine blood work (a complete blood count and serum biochemistry profile) to rule out metabolic causes of skin scaling. In many cases, walking dandruff can be diagnosed by physical examination and observation of the mites crawling along the top of the dog’s back. A simple “touch tape” technique is frequently used to take a sample of the flaky skin debris. This involves taking a piece of acetate tape and pressing it to the skin and hair where the mites are evident. The plaque-like scales will stick to the tape and can then be examined under a microscope, without staining, for very effective confirmation of their cause. A flea comb is another highly efficient way to obtain samples. Deep skin scrapings and fecal flotation can also be used to collect samples, although these techniques are rarely necessary. Cheyletiella mites are fairly large and frequently can be seen with the naked eye. However, it is more reliable to inspect them using a standard hand-held magnifying lens or a microscope. In those cases where the mites cannot easily be identified, the veterinarian may recommend treating the dog with an insecticide and evaluating its response to treatment. Sometimes, walking dandruff in dogs is not even suspected, much less identified, until lesions (sores) and intense itchiness develop in people living in the same household who have become infested with the Cheyletiella mites.
The main symptoms of walking dandruff – itchiness, scratching and skin scaling - can mimic those of other, more common diseases, such as flea bite dermatitis, food allergies, seborrhea and sarcoptic mange.