What etiological agent causes scabies (sarcoptic mange)?
Sarcoptes scabiei var canis
What species does Sarcoptes scabiei var canis typically infest?
Dogs Note: It has been reported to rarely infest cats
How is scabies spread?
it is highly contagious through direct contact or fomites
Where does the life cycle of Sarcoptes scabiei var canis take place? What are the life stages?
Entirely on the host in 17-21 days. Egg, larva, nymph, adult
How long do scabies mites typically live on the host?
for 2-4 weeks
What can clinical signs due to Sarcoptes scabiei var canis be the result of?
mechanial irritation, toxic secretions of the mite, and/or hypersensitivity reactions to the mite or substances elaborated by the mite
Is there zoonotic potential from scabies?
Yes - the zoonotic potential is high; exposure results in extremely pruritic papulopustular eruptions
What is the hallmark of scabies?
What are the key historical clues for scabies?
Multiple animals showing signs in the same household, the onset of pruritus after boarding or kenneling, progressive pruritus, progressively less response of the pruritus to glucocortiocoid therapy, the presense of humans in the household with lesions
What lesions are associated with scabies?
papulopustular eruptions, hemorrhagic crusts, erythema, scaling, and patchy alopecia
What lesions are associated with chronic scabies?
Lichenification and hyperpigmentation
Where are lesions due to scabies classically distributed?
in the periorbital area (P), the margins of the ears (E), elbows (E), and lateral aspects of the extremities (L)
Aside from skin lesions, what also is a consistent finding with patients that have scabies?
generalized peripheral lymphadenomegaly
What reflex is highly suggestive scabies?
the pinna-femoral reflex
How do you diagnose scabies?
Skin scrapings - you may need to do up to 80 scrapings on a dog before finding evidence of scabies
What can you centrifuge with scabies scrapings to concentrate the mites?
What must you always ask owners when an animal is suspected of having scapies?
if there is human involvement
Can you do a fecal flotation to diagnose scabies?
Yes you can check one - sometimes the patients ingest the mites, but it shouldn't be the first test you do
In cases of scabies, what does histopathology of lesional skin show?
it shows perivascular dermatitis with eosinophilic infiltrates
What are the general principles of therapy for scabies cases?
1. Treatment should be initiated without ID of mite, if the index is high 2. Treat all susceptible animals in the house - this includes house 3. Treat the environment by vacuuming, spray with flea sprays, and launder the bedding 4. Glucocorticoids can alleviate discomfort 5. Tell clients to see their physician if they have skin lesions
What may be necessary to do to long-haired dogs with scabies?
A total body clip
What will be helpful to remove the crusts and increase the effectiveness of the treatment dips?
Keratolytic baths (sulfur/salicylic acid)
What are effective topical dips to treat scabies?
2-3% lime sulfur applied weekly for 3-6 treatments and Amitraz - 2-3 rinses weekly
What is the topical treatment of choice for patients with scabies?
Selamectin (Revolution) - three doses at 2-3 week intervals
What other topical treatments can be given to patients with scabies?
Moxidectin (Advantage-Multi) and Fipronil (Frontline) spray
Theere are two systemic therapies for scapies, what are they?
Ivermectin and milbemycin (Interceptor)
Ivermectin is not currently approved in the US for use in dogs and cats to treat scabies. However, what is the recommended dosing?
0.3 mg/kg orally repeated weekly for 3-4 doses
What side effects are associated with Ivermectin?
neurologic in nature and may include sudden death
What is the recommended dose for milbemycin (Interceptor)?
It is not readily available as of 2014, but the recommended dose is 2/mg/kg, twice weekly for 3 weeks