Pruritis 3 - Ectoparasites

Question 1

What ectoparasites cause pruritus in dogs?

Answer 1

Sarcoptes 
Demodecosis 
Cheyletiella 
Lice 
Chiggers

Question 2

T/F: Sarcoptes in very contagious and zoonotic

Answer 2

True

Question 3

Clinical signs of sarcoptic mange?

Answer 3

Intensely pruritic - positive pedal reflex

Poorly steroid responsive
Lesions - papule, alopecia, erythema, crust, excoriation

Affected - hocks, elbows, pinnae margins, ventral abdomen, and chest

Predilection for sparsely haired areas

Secondary weight loss

Question 4

How can you diagnose sarcoptic mange?

Answer 4

Response to treatment
Positive pinnae-pedal reflex

Extremely difficult to find mite on scraping —> take at least superficial scraping form different sites

Fecal flotation
—> often mites are found in feces

Question 5

What is the treatment for sarcoptic mange?

Answer 5

Topical dips

• anti-seborrhetic shampoo
• 2-3% lime sulfur (dilates follicles)
• amitraz

Topical spot-on / systemic

• selectamin
• modixectin (off label)
• ivermectin
• milbemycin
• fipronil

Treat all affected and in-contact dogs
Treat secondary pyoderma
Clean all bedding/kennels

Question 6

What demodex sp in in dog?

Answer 6

Demodex canis

Question 7

What demodex sp is in cats?

Answer 7

Demodex cati

Question 8

What are the two types of demodecosis?

Answer 8

Localized or generalized

Question 9

What type of demodex is usually in young patients? Where is is usually found on the body?

Answer 9

Localized; face and forelimbs

Question 10

What type of demodecosis is found in dogs <18months or adult onset? Where on the body is it found?

Answer 10

Generalized; all over the body and on feet

Question 11

If a dog has a generalized demodecosis you should do what as part of your diagnostic?

Answer 11

Look for underlying disease

Skin scrape - deep, warm and squeeze the skin

Chronic fibrotic areas - biopsy and histopatholgoy

Question 12

What is the DDX for folliculitis ?

Answer 12

Fungal — dermatophytosis

Bacterial

Demodex

Question 13

How do you treat localized demodecosis ?

Answer 13

Mild dz usually heals spontaneously over 6-8wks

Use in Amitraz is not recommended — encourages mite resistance

local application of an antiparasitic ear ointment or a benzoyl peroxide can be used

Question 14

How do you treat a generalized demodecosis ?

Answer 14

Treatment is long term —> intensive and prognosis could be poor
AMITRAZ!

30-50% of dogs <1yr with generalized demodecosis will heal spontaneously

Over 1yr - definitely needs treatment

Mite counts should be recorded - always manage deep pyoderma aggressively

Clinical cure precedes parasitological cure — continue treatment until at least skin scraps are negative for 3consecutive weeks

Question 15

What procedure do you follow to maximized amitraz treatment efficacy?

Answer 15

Clip long haired dogs

Warm water soak/shower help dilate follicles

Use a benzoyl peroxide shampoo to remove crust and dilate follicles

Sponge on prep and leave on - DO NOT rinse off

Feet may be specifically managed with a Triatix/mineral oil mixed applied twice weekly

Maintenance dipping may be required for life

Question 16

T/F: ivermectin is labeled for treatment of demodecosis

Answer 16

False

This is extra label used

Be careful “white feet dont treat” - PCR test for MDR-1 gene mutation

Question 17

What are signs of ivermectin toxicity ?

Answer 17

Weakness, ataxia, and sleepiness

Question 18

What are alternative treatments to amitraz for demodecosis

Answer 18

Ivermectin (off label)

Doramectin
Interceptor
Advantage multi

Question 19

What is the name of the walking dandruff mite?

Answer 19

Cheyletiella mite

Question 20

Clinical signs of Cheyletiella mites?

Answer 20

Walking dandruff
Scaling
Pruritus , positive scratch reflex, papular crust

Question 21

T/F: cheyletiellosis is zoonotic

Answer 21

True

Question 22

How do you diagnose cheyletiellosis

Answer 22

Direct visualization - crawling on fur

Acetate tape test
Flea comb

Question 23

Treatment of cheyletiellosis?

Answer 23

All in-contact animals
Treat environment

Topical

• shampoo —> selenium sulphide, permethrin, lim sulphur
• spot on - selectamin, moxidectin every two weeks
• fipronil
• Amitraz dips

Treatment length - 6week minimum

Question 24

What nematode can cause a dermatitis, what are the clinical sings, and how could you diagnose?

Answer 24

Ancylostoma spp or uncinaria spp

Clinical signs

• interdigital areas
• pruritic
• erythema, alopecia, thickening

Diagnose by fecal float

Question 25

How long will you treat a dog with hookworm dermatitis>

Answer 25

For 6weeks..

The prepatent period is 3 weeks.. repeat dose every 2 weeks and give 3 treatments

Question 26

Trombicula mites are AKA?

Answer 26

Chiggers or harvest mites

Question 27

What time of year do you see chiggers and where are they found?

Answer 27

Spring and fall

Throughout central USA

Question 28

T/F: both larvae and adults of chigger mites are found on the animal

Answer 28

False

Adults are almost never found on adult —> in environment, lay eggs in soil, larvae hatch and crawl onto host

Question 29

Chigger mites are localized to what part of the animal>?

Answer 29

Legs, head, and abdomen

Cats — inside ears

Cause pruritus, papules, and erythema

Question 30

Diagnosis of chiggers?

Answer 30

Skin scrape

Red colour mites

Question 31

Treatment of chiggers?

Answer 31

Two pyrethrin dips spaced two weeks apart

Topical antiparasitic drugs

Topical/oral prednisolone to alleviate pruritus