With a skin biopsy, if the mite is captured in the sample it is diagnostic. If not, it is only suggestive. Findings in a skin
biopsy from a patient with Cheyletiella include epidermal acanthosis with moderate to severe orthokeratotic hyperkeratosis,
mixed-inflammatory infiltrate of the superficial dermis with eosinophils, lymphocytes, histiocytes and plasma cells and variable
edema. Eosinophil numbers may be downgraded, depending upon previous steroid therapy.
There are various topical and systemic therapies for Cheyletiella mites. They should include treatment of all exposed animals
as well as appropriate environmental treatments.
Topical treatments for both dogs and cats include lime-sulfur dips every five to seven days for three to four applications,
pyrethrin shampoos weekly for three to four weeks or Frontline spray (1 spritz/lb body weight every three weeks for two applications).
Because of nasal sequestration of mites, systemic therapies are probably more effective.
Systemic therapy choices for dogs include:
- Ivermectin 200 mcg/kg SQ or orally once weekly for three weeks (The dog must be heartworm-negative first and not a herding
breed or white German shepherd. Use cautiously in older dogs of any breed.)
- Interceptor at 1 mg/kg every other day for 14 days or 1 mg/lb body weight once weekly for three weeks (must be heartworm-negative
- Advantage Multi once monthly for two months
- Revolution one tube topically every 15 days for three treatments
- Amitraz dips once weekly for three weeks or every two weeks for two dips
Systemic therapy choices for cats:
- Ivermectin 200 mcg/kg SQ once weekly for three weeks or every two weeks for two doses
- Interceptor 1 mg/lb once weekly for three to four weeks
- Revolution one tube topically every 15 days for three doses
Treatments for either species should take into account the pet's physical condition.
Patients with underlying internal medicine disease need to be prescribed the safest treatment for their condition.
Once thought to be uncommon, Cheyletiella mites have resurfaced in large numbers.
Because there have been strides in treating fleas with newer, easier and safer products, perhaps we are seeing a resurgence
in these parasite populations.
I am certain that once you start routinely checking pets, even if it's just to flea-comb each patient, you may be surprised
at what you find.
Dr. Jeromin is a pharmacist and veterinary dermatologist in private practice in Cleveland, Ohio. She is a 1989 graduate of
The Ohio State University College of Veterinary Medicine and an adjunct professor at Case Western Reserve University's College
of Medicine in Cleveland.