Scabies & Demodex

Question 1

What is scabies caused by?

Answer 1

Sarcoptes scabei var. canis

Question 2

Is the scabies mite host specific?

Answer 2

No; zoonotic disease

Question 3

How long is the scabies mite life cycle?

Answer 3

3 weeks

Question 4

How is scabies transmitted?

Answer 4

Direct contact

Question 5

What is the pathogenesis of pruritis with scabies?

Answer 5

Hypersensitivity
Mechanic irritation
Pruritogenic substances from saliva and feces

Question 6

What are the classic sites of infection for scabies?

Answer 6

Ventral abdomen
Pinnae
Hocks
Elbows

Question 7

What is the primary lesion for scabies? Secondary lesions?

Answer 7

Primary - papule

Secondary - crusts, alopecia, excoriations, secondary infections

Question 8

What are some clinical signs of chronic scabies?

Answer 8

Hyperpigmentation
Lymphadenopathy
Weight loss
Hyperglobulinemia

Question 9

What is norwegian scabies?

Answer 9

Rare form that causes thick crusts
Numerous mites
Little pruritus
Seen in immunosuppressed animals

Question 10

What is scabies icognito?

Answer 10

Well groomed animals
Intense pruritus
No lesions

Question 11

How do you diagnose scabies?

Answer 11

Skin scrape (pinnae, elbows, hocks)

Question 12

What is the treatment for scabies?

Answer 12

Topical:
Lime sulfur dips
Selamectin
Fipronil

Systemic:
Ivermectin
Milbemycin

Question 13

What is feline scabies?

Answer 13

Notoedric mange, caused by Notoedres mite

Causes extreme pruritus on head and neck

Question 14

What is cheyletiella?

Answer 14

“Walking dandruff”
Produce digesting enzymes and eat dissolved skin of host
Causes irritation, hairloss, scabs
3 types for dogs, rabbits, cats

Question 15

Is cheyetiella zoonotic?

Answer 15

Yes, can cause papular eruption and pruritus
Cannot reproduce on human skin
Self-limiting

Question 16

How long is the lifecycle of cheyetiella?

Answer 16

3 weeks

Question 17

How do you treat cheyetiella?

Answer 17

It’s easily killed by most insecticides
Environment should be cleaned

Don’t use fiipronil on rabbits

Question 18

What is pediculosis?

Answer 18

Lice, two types:
Biting (trichodectes canis)
Sucking (linognatus setosus)

Question 19

Is pediculosis zoonotic?

Answer 19

no, host-specific

Question 20

How is pediculosis diagnosed?

Answer 20

Physical identification of lice and eggs

Question 21

How is pediculosis treated?

Answer 21

Clip coat in long-haired animals
Treat to cover lifecycle
Pyrethrin, fipronil, lime sulfur

Question 22

How long is the lifecycle of the demodex mite?

Answer 22

25-30 days

Question 23

How is demodex transmitted?

Answer 23

Mites transmitted to pups from bitch in the first 1-3 days of life
Present in low numbers in healthy post-natal dogs
Disease is caused by abnormal proliferation

Question 24

What is the pathogenesis of demodecosis?

Answer 24

Deficient cell-mediated immune response
Genetics (autosomal recessive)
Immunosuppression
Bacterial folliculitis

Question 25

Is demodex contagious or zoonotic?

Answer 25

No

Question 26

What are the clinical signs of demodex?

Answer 26

``` Papules/pustules, erythema Alopecia Scaling, crusting Comedones Patchy alopecia Hyperpigmentation ```

Question 27

What are the three techniques to diagnose demodex?

Answer 27

Deep skin scrape Hair plucks Biopsy

Question 28

What are the different types of demodex?

Answer 28

Juvenile onset Adult onset Localized Generalized

Question 29

For breeding animals, why would you want to wait and see if localized demodex will eventually become generalized?

Answer 29

To know/discuss prognosis To make recommendations about neutering

Question 30

What percent of localized demodicosis will resolve on its own? What percent will generalize?

Answer 30

90% will clear | 10% will generalize

Question 31

How do you treat juvenile demodicosis?

Answer 31

Benign neglect Antibiotics Benzoyl peroxide shampoo (2-3%.. less than human dose!) Deworming, good diet, etc.

Question 32

Why would you not treat demodicosis with miticides?

Answer 32

To know if it will become generalized | Prevent unnecessary medical treatment

Question 33

How should you monitor localized demodicosis?

Answer 33

Deep skin scrapes in 5 spots If mite count decreases and lesion is resolving. Recheck q4weeks until resolves If mite count increases, and other sites are positive, may be progressing to generalized

Question 34

What is it called if demodicosis involves two or more feet?

Answer 34

Pododemodicosis

Question 35

What should be considered for adult demodicosis?

Answer 35

If there is any underlying immunosuppression... steroid misuse, endocrine disease, metabolic disease, neoplasia

Question 36

What percent of juvenile generalized demodicosis will self-clear?

Answer 36

50% self clear | 50% require treatment

Question 37

How do you treat generalized demodicosis?

Answer 37

Miticide (Amitraz, milbemycin, ivermectin, moxidectin, bravecto) Antibiotics Benzoyl peroxide

Question 38

When should you not use amitraz to treat demodicosis?

Answer 38

Patients that are: toy breeds, sick, old, have extensive ulcerations Owners that have: asthma diabetes taking MOA (Parkinson's)

Question 39

What is the only FDA approved treatment for demodicosis?

Answer 39

Amitraz

Question 40

Why should you not give ivermectin to collies, shelties, australian shepherds, etc?

Answer 40

MDR1 gene deletion causes Defect in proton pump (P-glycoprotein) Drug crosses into brain but not pumped out efficiently

Question 41

How long should you treat demodicosis with ivermectin?

Answer 41

Until 3 negative skin scrapes at 4 week intervals 5 sites each time, always include muzzle and feet

Question 42

What percent of generalized demodex is juvenile?

Answer 42

97%

Question 43

What breeds are hard to cure of demodex?

Answer 43

OESD Afghan Hound Shih Tzu Lhasa Apso

Question 44

What species of mites cause feline demodicosis?

Answer 44

D. Cati | D. Gatoi

Question 45

What is the difference between D. Cati and D. Gatoi?

Answer 45

D. Cati - follicular mite, due to immunosuppression, variably pruritic, need deep scrape D. Gatoi- stratum corneum mite, contagious, very pruritic, superficial skin scrape, common in Texas

Question 46

How do you treat feline demodicosis?

Answer 46

D. Cati- ivermectin | D. Gatoi- ivermectin, lime dip

Question 47

How can you tell the difference between D. Cati and D. Gatoi under the microscope?

Answer 47

D. Cati is long and narrow | D. Gatoi is short and wide