Derm2- Demodicosis

  1. What are the 3 causes of folliculitis?
    bacterial folliculitis (superficial pyoderma), demodicosis, dermatophytosis
  2. What are the 3 canine demodectic mites?
    Demodex canis, short-tailed mite (Demodex cornei), Demodex injai
  3. Where does each of the following mites live on the body:
    D. canis
    D. cornei
    D. injai
    • D. canis- hair follicle and sebaceous glands
    • D. cornei- surface
    • D. injai- hair follicle and sebaceous glands
  4. Do Demodex mites live in the environment?
    no, their entire life cycle on the skin
  5. If demodex is normally on the skin, why do some get generalized demodectic mange?
    [not completely understood] possible role of mite-specific immunoincompetence, depressed T cell function, immunosuppressive factor from the mite
  6. How is demodex usually transmitted?
    from bitch to pup during nursing
  7. What are the categories and sub-categories of disease associated with Demodex?
    • Localized
    • Generalized: juvenile and adult-onset
  8. Demodicosis is NOT __________ unless there is...
    pruritic; secondary infection.
  9. How/when does localized demodicosis usually present?
    <1 year old (3-6 months), 90% spontaneously resolve in 4-8 weeks, focal areas of alopecia, scale, erythema, hyperpigmentation, lesions are periocular/perioral/forelimbs
  10. Describe generalized demodicosis.
    hereditary predisposition- dogs should not be bred if they have generalized demodicosis (their dam and sire should also be sterilized)
  11. Clinical signs of generalized demodicosis. (8)
    scaly alopecic patches, erythema, crusting, follicular plugging, comedones, hyperpigmentation, +/- greasy skin (D. injae), +/- pustular form
  12. Describe the pustular form of generalized demodicosis. (12)
    [life-threatening] gram-negative deep infection, alopecia, papules, pustules, draining tracts, cellulitis, ulcers, erosions, depressed, lethargic, lymphadenopathy
  13. What are the 4 forms of generalized demodicosis?
    squamous, greasy, pustular, pododemodicosis
  14. What are potential triggers for adult-onset generalized demodicosis? (6)
    glucocorticoids (most common), Cushing's, chemotherapy, hypothyriodism, neoplasia, idiopathic (if can't identify underlying cause)
  15. What are the cut-offs for juvenile-onset demodicosis?
    • <12 months old
    • <18 months old in giant breeds
  16. How do we diagnose demodicosis? (4)
    deep skin scraping for follicular mites, superficial scrapes for surface mites (D. cornei), +/- hair plucks (not sensitive, neg doesn't rule out), +/- some cases may require biopsy
  17. Describe the diagnosis of generalized demodicosis (as opposed to localized)?
    • generalized if:
    • entire body region affected
    • one or more feet
    • >5 localized lesions
  18. What must you be sure to do during the course of diagnosis and treatment of demodicosis?
    count mites and record sites, are mites alive or dead, life stages present- do this at every recheck to follow progression
  19. Demodex is usually easy to find if you're doing your skin scrapes properly, UNLESS... (2)
    fibrotic lesions, chinese shar-pei, OES, scottie [breeds....difficult to find mites]
  20. When should you biopsy to confirm or rule out demodicosis? (2)
    fibrotic lesions, [3 breeds] shar-pei/OES/scottie
  21. What additional tests need to be run with adult-onset demodicosis? (4)
    CBC/Chem, UA, thyroid test [additional tests may be warranted on a patient-to-patient basis]
  22. How do you treat localized demodex? (2)
    NONE- recheck every 2-3 weeks, +/- treat secondary pyoderma
  23. What should you NEVER use when treating Demodex?
    steroids (it is caused by immune suppression)
  24. How do you treat generalized demodicosis? (5)
    • stop glucocorticoids if applicable
    • control secondary bacterial infections
    • spay/neuter
    • amitraz dips every 2 weeks w/ concurrent deep scrape; continue until 2 consecutive negative scrapes (done in hospital...potentially dangerous to people)
    • Extra-label txts: ivermetin, milbemycin, dramectin, fluralaner, moxidectin/imidacloprid
  25. What is the only form of generalized demodicosis in which you may not have to provide any treatment?
    mild, squamous juvenile demodicosis
  26. How do you perform an amitraz dip?
    wear PPE, clip dog's hair, bathe for 15 min in benzoyl peroxide, soak for 15 min in amitraz, blow dry (DO NOT RINSE, DO NOT LET DOG GET WET)
  27. When is a dog considered cured from generalized demodex?
    1 year from date of last dip w/ a negative deep scrape [some are never cured, just controlled]
  28. What should you do if a dog has a reaction after an amitraz dip?
    RINSE THE DOG, administer Yohimbine
  29. What should you do if amitraz dips aren't decreasing mite numbers?
    extra-label: increased dip to every week or increase conc for 0.05%
  30. What extra-label products are commonly used to treat demodicosis? (6)
    Ivermectin, Milbemycin, large animal amitraz, doramectin, moxidectin/imidacloprid, fluralaner
  31. In what animals should you NOT use ivermectin?
    herding breeds of any type
  32. What causes ivermectin sensitivity in Collies/etc?
    P-glycoprotein mutation (transports ivermectin from brain back to peripheral circulation), which is a product of ABCB1 gene, which functions as a drug efflux pump
  33. How do you use extra-label ivermectin to treat demodicosis?
    LA ivomec given orally once a day (start low dose and increase), txt continued for 1-2 months after 2 negative consecutive deep skin scrapes
  34. What 3 drugs should absolutely be avoided when using ivomec to treat demodicosis?
    spinosad (comfortis), ketoconazole, cyclosporine
  35. How is milbemycin used for demodex treatment?
    same as ivomec
  36. What are the 3 demodex mites of cats and where does each live on the body?
    • Demodex cati- follicular mite
    • Demodex gatoi- surface mite
    • Unnamed species
  37. Generalized demodicosis with D. cati has been associated with? (7)
    DM, FeLV, FIV, hyperadrenocorticism, SLE, immunosuppressive drugs
  38. What underlying diseases have been associated with D. gatoi? (3)
    immunosuppressive drugs, DM, CAFR
  39. Clinical signs of D. cati? (8)
    chin/periorbital alopecia and scaling OR generalized with alopecia, scaling, papules, crusting, erythema, ceruminous otitis externa
  40. What is unique about D. gatoi infection? (2)
    pruritic, contagious
  41. How do you diagnose feline demodicosis? (3)
    superficial and deep skin scrapes, rule out concurrent viruses
  42. How do you treat feline demodicosis? (3)
    localized is self-limiting, generalized should be dipped in lime sulfur weekly to 4-6 weeks; for D. gatoi, all in contact cats should also be treated
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Derm2- Demodicosis
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