Dermatology - Scabies Flashcards
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?
intense pruritus
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?
KOH/Sugar
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?
- 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)
A
Topical
B
yes
C
topical application: 3 doses at 2 week intervals
D
oral
E
no
F
0.3 mg/kg orally weekly for 3-4 weeks
G
topical
H
yes
I
weekly rinses after a total body clip
J
topical
K
no
L
weekly rinses x 2-3 weeks
M
oral
N
no
O
various protocols: see notes
P
topical
Q
no
R
liberal soaking of patient: repeat in 1-2 weeks
S
oral or subcutaneous
T
no
U
0.2-0.25 mg/kg, PO weekly for 3-6 weeks
V
topical
W
yes
X
three applications at 2 week intervals
Y
oral
Z
yes (flea/tick)
AA
label dose given PO once montly
