Mites Flashcards
demodex
commensal mite found in hair follicles of mammals
demodex transmission
direct contact
transmitted from dam during nursing in first 2-3 days
pathogenesis of demodicosis
overgrowth of mites within hair follicles
in healthy animals - innate immune system controls demodex populations in the skin
in immunocompromised animals - unable to control population –> demodicosis
canine demodicosis species
d. canis
d. injai
D. canis
commensal in hair follicles of dogs
shorter tail (~1x body length)
D. injai
not commensal; found in sebaceous glands of terrier breeds
longer tail (~2x body length)
clinical signs of D. canis demodicosis
- alopecia (focal to multifocal/generalized)
- minimal to NO pruritus
- folliculitis
- papules, pustules
- comedones
- +/- erythema
- secondary bacterial infection
localized demodicosis - signalment
juvenile onset
3 to 6 months
localized demodicosis - pathogenesis
immature immune system unable to regulate demodex populations
localized demodicosis lesions
1-4 areas of focal alopecia +/- erythema
lesions <2.5 cm
most often located on face or front limbs
generalized demodicosis - signalment
juvenile or adult onset
generalized demodicosis pathogenesis
multifocal or generalized overgrowth of demodex mites
generalized demodicosis lesions
multifocal, patchy, or generalized alopecia w/ erythema
variable pruritus usually only seen if secondary infection present
some dogs may be systemically ill
juvenile onset demodicosis
dogs ranging from 3 months to 2 years
staffies, sharpeis, frenchies, pitties, boxers, bostons
what causes juvenile onset demodicosis
genetic defect leading to a dynsfunction in control of demodex
juvenile onset demodicosis lesions
multifocal, patchy alopecia
nodules
draining tracts
adult onset demodicosis
dogs > 2 years
what causes adult onset demodicosis
immunosuppression - systemic illness vs medication induced
diseases: cushings, hypothyroidism, diabetes mellitus, neoplasia
drugs: corticosteroids, apoquel
adult onset demodicosis lesions
marked erythema
ulcerations
hemorrhagic crusting
deep secondary infections
pododemodicosis
demodicosis affecting the front paws or all 4 paws ONLY
erythema, hyperpigmentation, swelling, nodules, draining tracts
SIGNIFICANT swelling of the paws
what breed of dog is most affected by demodex injai
terrier breeds
clinical signs of D. injai
moderate to severe pruritus
greasy dorsal stripe
NO alopecia
diagnostics for demodex
- signalment and history
- PE (alopecia vs greasy dorsal stripe)
- deep skin scraping
- trichoscopy
- acetate tape
- histopathology
treatment for localized demodicosis
benign neglect
OR
topical therapy (benzoyl peroxide, topical antiseptics)
treatment for generalized demodicosis
- isoxazolines (flea/tick medication)
- topical +/- systemic antibiotics
continue treatment for 1 month after 2 negative skin scrapings
how to monitor treatment progress of demodicosis
repeat deep skin scrapings from same locations once monthly
what is considered a negative skin scraping
NO mites present (not even dead mites)
prognosis for demodicosis
good with owner compliance
some may require lifelong therapy
what species of demodex affect cats
D cati
D gatoi
D. cati
commensal found in hair follicles in cats
D. gatoi
not commensal; found in stratum corneum
signalment for feline demodex
D. cati: very sick cats
D. gatoi: cats in warm, humid climates + multicat households
clinical signs of feline demodicosis
D. cati: non-pruritic patchy/multifocal alopecia
D. gatoi: mild to marked pruritus, alopecia from self trauma/overgrooming
diagnostics for feline demodicosis
D. cati: deep skin scraping
D. gatoi: superficial skin scraping, fecal float
treatment for feline demodicosis
fluralaner (bravecto) topical
what species of mite causes sarcoptic mange
sarcoptes scabiei
how is sarcoptes transmitted
direct transmission from infected host (wild canids) or environment
SHORT life cycle - 3 to 4 weeks
pathogenesis of sarcoptes
adult females burrow tunnels and lay eggs in the stratum corneum causing a type I hypersensitivity reaction
clinical signs of sarcoptic mange
- extremely severe pruritus
- non to poorly responsive to corticosteroids
- signs of self trauma (erythema, papules, alopecia, excoriations, scaling, crusts, lichenification)
distribution of sarcoptes
ear margins, legs, elbows, hocks, ventrum
diagnosis of sarcoptes
clinical signs (SEVERE pruritus) + pathognomonic distribution
pinnal-pedal reflex
superficial skin scrapings
treatment for sarcoptes
isoxazolines
rapid mite die off may cause hypersensitivity reaction
- treat with prednisone x3-4 days
cheyletiellosis
“walking dandruff”
lives on the surface layer of skin, crawls around the hair and feeds on the skin
what species of cheyletiella affects cats
C. blakei
what species of cheyletiella affects dogs
C. yasguri
is cheyletiella contagious between individuals of the same species
yes
NOT transmitted between different species
clinical signs of cheyletiella
multifocal to diffuse heavy scaling to crusting
miliary dermatitis (cats)
walking dandruff appearance
mild to severe pruritus
distribution of cheyletiella lesions
dorsal
diagnosis of cheyletiella
history (no flea protection)
clinical signs
acetate tape
superficial skin scrapings
can monitor response to empiric treatment
treatment of cheyletiella
isoxazolines
