Small Animal Dermatology, 3rd edition

CHAPTER 42 SARCOPTID MITES 635

 Nonseasonal extremely intense pruritus.

 Zoonosis: pruritic papular dermatitis affecting in-contact humans.

 Sources of exposure:
Catteries and multiple cat households
Living outside
Kennels
Veterinary offices
Groomers
Animal shelters.

CLINICAL FEATURES

 Sarcoptes scabieiinfestation:
Alopecia and erythematous rash: pinnal margins, elbows, hocks, ventral

abdomen, and chest (Figures 42.7–42.9).

Lesions on pinnal margins and elbows: vary from barely perceptible scaling to

alopecia or thick crusts; ear canals not affected.

Chronic: periocular and truncal alopecia; thick secondary crusts, excoriations,

and secondary bacterial folliculitis; diffuse papular eruption.

Possible peripheral lymphadenopathy.

Frequently bathed dogs will often have chronic pruritus with minimal skin

lesions (“scabies incognito”).

Often minimal or no response to antiinflammatory doses of steroids.

Multiple dog households: more than one dog typically pruritic; asymptomatic

carriers rare.

 Notoedres catiinfestation:
Intense pruritus with thick adherent crusting dermatitis
Areas most affected include the pinnae, head, face, neck and forelegs; may gen-

eralize from grooming behavior (Figures 42.10–42.12)

Peripheral lymphadenopathy is common

Cats may become anorexic and emaciated if left untreated.

 Cheyletiellaspp. infestation:
Characterized by excessive scaling and variable pruritus (Figures 42.13, 42.14)
“Walking dandruff” due to large mite size: mites may be visible without magni-

fication

Cocker spaniels, poodles, long-haired cats, and rabbits may be asymptomatic

carriers

Young animals most at risk

Dorsal orientation of scale with minimal erythema is a common initial symptom

Some cats may exhibit bilateral and symmetric alopecia.

 Otodectes cynotisinfestation:
Pruritus and resultant excoriation usually located around the ears, head, and

neck; may generalize

Thick, red-brown or black crusts within and around the ear canal (Figure 42.15).