Lecture: Demodicosis

Question 1

pathogenesis Demodex

Answer 1

• Deficient cell mediated immune response
• Genetics, autosomal recessive
• Immunosuppression
• Bacterial folliculitis

Question 2

Any dog (animal I think) positive for demodex needs to be

Answer 2

on an antibiotic

(something about staph receptor on demodex…blah blah blah)

Question 3

Demodex and contagiousness

Answer 3

Not contagious

Question 4

Demodex

CS

Answer 4

• Papules/pustules, erythema
• Alopecia
• Scaling, crusting

Question 5

common places for demodex

Answer 5

face and feet

Question 6

Comedones

Answer 6

• follicular plugging (blackheads)
• comedeones on feet, MUST SCRAPE

Question 7

DDX for comedones

Answer 7

• endocrine dz
• demodex

Question 8

Grey patchy skin from far away

Answer 8

• thick folliculitis
• think comedones
• scrape for demodex

Question 9

Demodex lives inside

Answer 9

hair follicle

Question 10

Demodex DX

Answer 10

• Pinch, scrape in direction of hair, till blood
• pluck the hair (not as sensitive as a scrape)
• Biopsy where comedones are
  
  • shar pei
  • scar tissue (hot spots)
  • pododermatitis

Question 11

juvenile demodex

Answer 11

genetically inherited dz….?!?!

Question 12

Adult demodex indicates

Answer 12

an underlying disease

Question 13

If demodex on deep scraping is diagnosed

Answer 13

1. Is it generalized?
   
   • scrape 5 places total
2. If it’s not generalized, will it become generalized?
   
   • don’t treat, wait and see (if a breeding animal)

Question 14

Localized Demodicosis - Prognosis

Answer 14

• 90 % of localized juvenile demodecosis will spontanously clear up

Question 15

Generalized demodicosis in breeding animals…

Answer 15

These animals should not have puppies

Question 16

TX localized juvenile demodicosis

Answer 16

• Antibiotics
  
  • topical benzoyl peroxide gel/shampoo
  • systemic if needed
• De-worming, good diet, HW, TLC

*do not use steroids, or anti-mite therapy

Question 17

Localized demodicosis

Answer 17

• monitor course of disease
  
  • recheck in 2-4 weeks
  • deep scrape skin same 5 spots
    
    • if mite counts decrease: lesion resolving, recheck q 4 weeks until negative
    • if mite counts inc: may be progressing to generalized

Question 18

Generalized Demodicosis

Answer 18

• 5 localized lesions or more
• involvement of an entire body region (ie: head)
• Involves 2 or more feet

Question 19

rate of clearance of gen juvenile onset demodicosis

Answer 19

50% of self clearance rate with an antibiotic

50% need anti-mite prescription

5% need lifelong treatment

Question 20

Adult onset generalized demodex

Answer 20

may precurse cushings, or other endocrine/metabolic dz

underlying immunosuppression…. (steroid misuse)

Question 21

Pododemodicosis

Answer 21

• very painful

Question 22

Generalized Demodicosis

TX

Answer 22

1. Miticide
2. Antibiotics
   
   • treat secondary bacterial infections
   • until neg 1st scrape
3. Benzoyl Peroxide shampoo (2.5%)
   
   • Follicular flushing

Question 23

Generalized Demodicosis

RX to kill mites

Answer 23

1. Amitraz = Mitaban
2. Ivermectin = Ivomec
3. Milbemycin = Interceptor (not available right now)

Question 24

Amitraz

Answer 24

• Topical
• only FDA approved tx
• MOI, alpha-2 adrenergic agonist, inhibits prostaglandin synthesis
• there are side-effects and it is labor intensive
• 6-9 weeks no response is a failure

Question 25

Amitraz (mitoban) pitfalls

Answer 25

* toy breeds and toxicity * Sick, old patients * extensive ulcerations

Question 26

Amitraz side effects

Answer 26

* Sedation/dull mentation * reversals * yohimbine * antipamezole * avoid use in owners with * asthma * diabetes (or animals with diabetes) * owner taking MOA: Parkinson's disease

Question 27

Amitraz failure

Answer 27

* No improvement after 6-9 months * untreated staph infection

Question 28

Ivermectin (Ivomectin)

Answer 28

* off label * Dose: * 400-600 microgram (0.4-0.6 milligrams) * HW prevention dose is 6 micrograms * **1% ivermectin is 10mg/mL** * toxic dose for collies/shelties is 100 micrograms ( 0.1 mg) * build up to final dose * monitor patient, educate patients * look for pupils and glazed look

Question 29

Ivermectin: white feet

Answer 29

dont treat

Question 30

Moxidectin

Answer 30

* Advantage multi * weekly or every other week

Question 31

Bravecto (flurolaner)

Answer 31

* 1 pill (lasts 12 weeks) eliminates 100% mites by day 56 * Safe for the white feets

Question 32

Generalized Demodicosis TX monitoring plan

Answer 32

* deep skin scrape * 5 sites * always include muzzle and feet * record mites * re-scrape same sites q 4 weeks * treat until 3 consecutive negative skin scrapes