Page 1517 - Clinical Small Animal Internal Medicine

165 Parasitic Skin Diseases 1455

of permethrins (>0.1%) are toxic to cats. Discarding
VetBooks.ir bedding is advised. In the United States, a licensed treat-
ment is selamectin (Revolution® for dogs, Zoetis) applied
topically every 30 days for two doses; however, for better
results most dermatologists recommend administering it
every two weeks for 3–4 treatments. Lime sulfur dips at a
2–3% concentration every week for 4–6 weeks is another
option. Ivermectin at 0.2–0.4 mg/kg can be given PO
every seven days or SC every 14 days for 4–6 weeks.
Milbemycin given orally at 2 mg/kg every week for 4–6
treatments has been shown to be effective. An imidaclo-
prid/moxidectin combination product (Advantage Multi)
is approved for the treatment of scabies in dogs and is
applied topically every 30 days for two doses. Amitraz
(Mitaban) solution at 0.025–0.03% applied over the whole
body every two weeks for three treatments or weekly for
Figure 165.8 Alopecia and thick yellowish crusts covering the ear
margin of a dog with scabies. 4–6 treatments should be effective. Fipronil spray applied
to the entire body every two weeks for three applications
Cats that become infested with Sarcoptes scabei var. is another treatment option. Doramectin can be given at
canis can develop dermatitis of the face and pinnae. 0.2–0.6 mg/kg SC every seven days for 4–6 weeks.
Papules and crusts are present. Dermatitis of the paws as Many of these patients have secondary infections
well as claw abnormalities may develop. Some cats may which should also be identified and addressed.
also develop crusting and scaling over the body. Pruritus Isoxazolines have been shown to effectively treat scabies
is a variable finding. Such infestations are uncommon as well. One dose of fluralaner (Bravecto) at a minimum
and rare cases have been noted in indoor cats not co‐ of 25 mg/kg orally or topically has been shown to elimi-
habiting with dogs. nate scabies mites. Afoxolaner (Nexgard) given at a mini-
mum dosage of 2.5 mg/kg PO for 1–2 monthly doses
Diagnosis should also eliminate these mites. Sarolaner (Simparica)
Infestations with this mite are often diagnosed based on can also be used at approximately 2 mg/kg PO for two
history, clinical signs, and response to therapy. Multiple monthly doses. There are no current publications relat-
superficial skin scrapings are required for diagnosis. ing to lotilaner (Credelio) and scabies mites, but the
Unfortunately, as few as 20% of skin scrapings may reveal author suspects it, too, would be efficacious at resolving
mites or eggs. Finding even one is diagnostic of canine sarcoptic mange. Antiinflammatory doses of corticoster-
scabies. It is suggested to scrape the aforementioned oids given for approximately one week may also help in
areas that are generally affected even in the absence of alleviating the pruritus caused by the mites.
lesions, as well as areas with papules and yellow crusts. The treatment protocols detailed under “Feline
Large numbers of mites are typically found on scrapings scabies” are also recommended for cats infested with
from cats infested with Sarcoptes scabei var. canis. Sarcoptes scabei var. canis. However, three applications
An additional supportive test is to demonstrate the of the moxidectin/imidacloprid (Advantage Multi)
pinnal‐pedal reflex. This test entails scratching the compound product applied every two weeks has been
pinnal edge with a resultant ipsilateral leg making a shown to be more efficacious in five cats with sarcoptic
scratching motion. Most dogs with scabies mites have mange than weekly ivermectin at 0.2 mg/kg SC for four
this reflex (sensitivity of 81.8%); however, it can be rarely weeks or selamectin (Revolution) administered every
positive in other diseases (specificity of 93.8%). two weeks for two treatments.
Laboratory testing utilizing an enzyme‐linked immu-
nosorbent assay (ELISA) is available in certain countries. Prognosis
This test has high specificity and sensitivity, but false‐ Most dogs with scabies are cured with treatment. Rare
negative results are possible. cases have been noted to be refractory to ivermectin and
selamectin. The selamectin cases may have been related
Therapy to poor application on densely coated dogs. In some
Affected as well as in‐contact dogs should be treated. cases, the author finds it beneficial to keep the patient on
Area treatments containing pyrethrins, permethrins or a monthly selamectin or an isoxazoline (unless it is flu-
combination of these are available for use in the home ralaner which is given every 3 months) when reinfesta-
environment, keeping in mind that high concentrations tion is considered possible.