Lecture 6 Pt 2 2/10/25 Flashcards
What is important to know regarding demodicosis?
-when and what lesions to scrape
-how to handle juvenile onset cases
-how to treat generalized cases
-how to educate the owner
What are the characteristics of canine demodemicosis?
-caused by follicular mite Demodex canis
-present in the skin of both healthy and diseased dogs
-no longer difficult to cure due to prevention meds
-“new variant” is Demodex injai
What are the characteristics of the Demodex life cycle?
-entire cycle spent on host skin within hair follicle and sebaceous gland
-receives nutrients from follicular keratinocytes, sebum, and epidermal debris
-20-35 day life cycle
-4 life stages
How is Demodex transmitted?
from bitch to puppies via direct contact within 2-3 days of birth
What is the pathogenesis of typical demodicosis?
depressed immune system/decreased T cell function/T cell exhaustion occurs due to disease or drugs and allows mites to cause dermatological dz
What is the pathogenesis of juvenile onset demodicosis?
genetic link via autosomal recessive genes
What are the clinical signs of demodicosis?
-alopecia
-erythema
-comedones
-papules
-pustules
-collarettes
-folliculitis and furunculosis
-secondary pyoderma and pruritus
What are the differential diagnoses for demodecosis?
-pyoderma
-dermatophytosis
How is demodicosis differentiated from other potential diagnoses?
skin scrape
How does the cause of localized demodicosis differ from the cause of generalized demodicosis?
-localized dz occurs with stress, parasitism, and/or poor nutrition
-generalized dz occurs with genetic causes or immune system suppression
What are the clinical signs of localized demodicosis?
-one or several small areas
-patchy alopecia
-erythema
-scale
-little to no pruritus
-face and forelegs primarily
What are the characteristics of localized demodicosis?
-can wait and monitor monthly
-excellent prognosis
-resolution of lesions indicates no genetic defect
-progression to generalized form indicates genetic defect
What are the clinical signs of generalized demodicosis?
-many lesions (greater than 6 to 12)
-involves the head, trunk, legs, and two or more feet
-large areas of alopecia
-erythema
-hyperpigmentation
-comedones
-papules, pustules, and collarettes
What are the characteristics of generalized pododemodicosis?
-may have feet involvement alone
-can occur with body lesions
-usually complicated by secondary bacterial infections
-difficult to scrape and treat
Where should you scrape to have the best chance of diagnosing demodicosis?
-areas of clustered comedones
-squeezing skin can make mites pop out
What are the workup steps for adult onset generalized demodicosis?
-CBC
-chem panel
-UA
-heartworm and fecal parasite testing
-total T4/TSH
-ACTH stim test or LDDST
-radiographs and/or ultrasound to look for neoplasia
What leads to improved prognosis for adult onset generalized demodicosis?
if the underlying cause can be identified and controlled/cured via treatmetn
What is the #1 cause of adult onset generalized demodicosis?
iatrogenic hyperadrenocorticism
What are the characteristics of Demodex injai?
-long-bodied mite
-preferes sebaceous glands and hair follicles
-causes a greasy stripe along dorsum +/- alopecia
-treatment is to introduce Demodex canis and allow normal mite to take over
How is demodicosis diagnosed?
-skin scrapings
-hair plucks
-acetate tape and squeeze
What is the treatment for demodicosis?
isoxazolines
Which species cause feline demodicosis?
-Demodex cati
-Demodex gatoi
What are the characteristics of Demodex cati?
-follicular mite similar to D. canis
-rare
-localized form can cause feline asthma aerokits
-generalized form can cause severe systemic disease
What are the characteristics of localized Demodex cati?
-most common form
-usually self limiting
-seen on nose, periocular skin, and neck
-variable pruritus
-causes alopecia, erythema, crusting, and hyperpigmentation
-can cause ceruminous otitis
What are the characteristics of generalized Demodex cati?
-same clinical signs as localized dz
-clinical signs on head, neck, trunk, and limbs
-often occurs with concurrent systemic disease, such as FeLV/FIV, diabetes mellitus, neoplasia, or cushing’s
What are the characteristics of Demodex gatoi?
-different from other Demodex mites; superficial mite that lives in the stratum corneum
-difficult to find/diagnosis
-makes cats pruritic
-has a short, fat body
-CONTAGIOUS to other cats
-treated with flea prevention meds
