Skin Scrapes and Their Parasitic Friends Clinical Pathology

Skin Scrape Fast and easy diagnostic tool Fast and easy diagnostic tool Inexpensive Inexpensive Should be one of the first diagnostics performed when diagnosing dermatologic disorders. Should be one of the first diagnostics performed when diagnosing dermatologic disorders.

Items needed for a skin scrape Blade (15 or 10) Blade (15 or 10) Mineral oil Mineral oil Microscope slide Microscope slide Microscope Microscope

Skin Scraping Technique Drop mineral oil on skin and/or slide. Drop mineral oil on skin and/or slide. Some prefer just to pass blade through oil instead of applying to skin.Some prefer just to pass blade through oil instead of applying to skin. Gently squeeze the skin area that you are scraping. Hold the blade perpendicular to the skin. Gently squeeze the skin area that you are scraping. Hold the blade perpendicular to the skin. Scrape until a small of amount of capillary blood oozes. (careful to not cut). Scrape until a small of amount of capillary blood oozes. (careful to not cut). May place coverslip if you like. May place coverslip if you like. Examine entire slide in a systematic fashion (start with 10x objective) Examine entire slide in a systematic fashion (start with 10x objective)

Skin Scrape Hints Scrape areas that have lesions Scrape areas that have lesions Scrape typical sites for particular ectoparasite Scrape typical sites for particular ectoparasite Ex: ear margins for Sarcoptic mangeEx: ear margins for Sarcoptic mange Do multiple skin scrapes Do multiple skin scrapes

Microscopic exam of the Skin Scrape Sample Identify any ectoparasites. Identify any ectoparasites. Determine live:dead ratios Determine live:dead ratios Determine life cycle stage Determine life cycle stage Eggs, immature, adultsEggs, immature, adults Determine numbers found Determine numbers found

Classification Class Class Acarina (mites and ticks)Acarina (mites and ticks) Family: Sarcoptidae and Psoroptidae Family: Sarcoptidae and Psoroptidae Sarcoptidae Sarcoptidae Mites that burrow through epidermisMites that burrow through epidermis Sarcoptes, Notoedres, Knemidocoptes species Sarcoptes, Notoedres, Knemidocoptes species Psoroptidae Psoroptidae Mites that reside on the skin surfaceMites that reside on the skin surface Psoroptes, Chorioptes, Otodectes species Psoroptes, Chorioptes, Otodectes species

Sarcoptes Scabei Oval with 8 legs Oval with 8 legs Long unjointed pedicles with suckers on the end. Long unjointed pedicles with suckers on the end. Terminal anus Terminal anus Eggs are oval/brownish Eggs are oval/brownish Entire life cycle is on host Entire life cycle is on host Female mites burrow through epidermis Female mites burrow through epidermis Over day period eggs are deposited in tunnels Over day period eggs are deposited in tunnels Larva emerge in 3-10 days. Larva emerge in 3-10 days.

Sarcoptes scabei symptoms EXTREME pruritis EXTREME pruritis Erythema, papules, scaling, crusting excoriations. Erythema, papules, scaling, crusting excoriations. Location: Ears, lateral elbow/hock, ventral abdomen (termed ventral “blowout”). Location: Ears, lateral elbow/hock, ventral abdomen (termed ventral “blowout”). Scratch reflex: When scratch on ear margin, dog scratches. Scratch reflex: When scratch on ear margin, dog scratches.

Sarcoptic Transmission, etc Transmitted through direct contact Transmitted through direct contact Diagnosis is through physical exam and history. Diagnosis is through physical exam and history. Since mites burrow into skin is very easy to get negative skin scrapes. Since mites burrow into skin is very easy to get negative skin scrapes. May have to do repeated skin scrapes May have to do repeated skin scrapes Zoonosis- mites are self-limiting in humans (Scabies). Zoonosis- mites are self-limiting in humans (Scabies).

Sarcoptic Treatment Revolution every 2 weeks (off label). Revolution every 2 weeks (off label). Ivermectin orally (extra-label). Ivermectin orally (extra-label). Paramite dips every 7-10 days (discontinued product). Paramite dips every 7-10 days (discontinued product). NEVER USE PARAMITE CONTAINING DIP IN CATS!!!!!!!!!!!!!!!!!!!!!!!!!!! NEVER USE PARAMITE CONTAINING DIP IN CATS!!!!!!!!!!!!!!!!!!!!!!!!!!!

Notoedres cati Roundish shape, smaller than scabie mite Roundish shape, smaller than scabie mite Dorsal anus Dorsal anus Same type of legs as scabie mite Same type of legs as scabie mite Mainly found in cats and occasionally in rabbits. Mainly found in cats and occasionally in rabbits. Location: Head, neck, ears, back of head and sometimes feet. Location: Head, neck, ears, back of head and sometimes feet. Crusts, excoriations, scales Crusts, excoriations, scales Pruritis Pruritis Is contagious Is contagious

Notoedres cati Treatment Revolution/ Ivermectin Revolution/ Ivermectin Keep isolated from other cats Keep isolated from other cats

Knemidocoptes Species Scaly leg mite of birds Scaly leg mite of birds Burrows under the scales of legs and toes Burrows under the scales of legs and toes Some species may cause depluming around head/neck. Some species may cause depluming around head/neck. Intense pruritis Intense pruritis Diagnose through skin scrape Diagnose through skin scrape Treatment: Ivermectin???? Treatment: Ivermectin????

Family Psoroptidae: Psoroptes cuniculi Ear canker mite of Rabbits Ear canker mite of Rabbits Lesions are dried, flaky crusts within the ear canal. Lesions are dried, flaky crusts within the ear canal. Pruritic Pruritic Treatment: Ivermectin Subcutaneously or topically at 2 week intervals. Treatment: Ivermectin Subcutaneously or topically at 2 week intervals. Do not clean ears- they are very painful and will bleed Do not clean ears- they are very painful and will bleed

Otodectes cynotis (ear mites) Mainly in ear canal, but may be found on any area of the body Mainly in ear canal, but may be found on any area of the body Mite feeds on epidermal debris Mite feeds on epidermal debris Produces intense irritation Produces intense irritation Usually bilateral Usually bilateral Contagious Contagious

Otodectes cynotis Diagnosis: Diagnosis: Grossly see with otoscope or with ear swabGrossly see with otoscope or with ear swab Treatment: Treatment: IvermectinIvermectin Acarexx topicalAcarexx topical PyrethrinsPyrethrins RevolutionRevolution

Demodex Species Host specific Host specific Reside in hair follicles and sebaceous glands Reside in hair follicles and sebaceous glands Small numbers are part of the normal skin flora of all dogs Small numbers are part of the normal skin flora of all dogs In immunodeficiencies, these mites increase in numbers In immunodeficiencies, these mites increase in numbers Possible genetic predisposition. Possible genetic predisposition.

Demodex species Demodex canis-dogs Demodex canis-dogs Demodex cati-cats Demodex cati-cats Dmodex gatoi-cats Dmodex gatoi-cats Demodex bovis-bovine Demodex bovis-bovine Demodex ovis-sheep Demodex ovis-sheep Demodex caprae-goat Demodex caprae-goat Demodex equi-horse Demodex equi-horse

Demodex canis and cati Elongated, spindle shape Elongated, spindle shape Adults: 8 stubby legs Adults: 8 stubby legs Larvae: 6 stubby legs Larvae: 6 stubby legs When diagnosing demodex cati need to rule out underlying disease like Feline Leukemia/FIV, etc.When diagnosing demodex cati need to rule out underlying disease like Feline Leukemia/FIV, etc.

Demodex gatoi Cats Cats Round, blunt bodyRound, blunt body ContagiousContagious PruriticPruritic Treatment: lyme- sulfur dipsTreatment: lyme- sulfur dips

Demodex canis clinical signs Often begin with localized lesions that spread. Often begin with localized lesions that spread. Patchy, multifocal or diffuse alopecia Patchy, multifocal or diffuse alopecia Variable erythema Variable erythema Silver/grayish scales Silver/grayish scales Papules or pustules Papules or pustules Variable pruritis-localized usually not pruritic unless infected Variable pruritis-localized usually not pruritic unless infected Secondary lesions- hyperpigmented, lichenification, crusty, ulcerated, folliculitis from secondary bacteria. Secondary lesions- hyperpigmented, lichenification, crusty, ulcerated, folliculitis from secondary bacteria.

Demodex canis Location of lesions: Location of lesions: Face, muzzle, legs/feet, occasionally trunk.Face, muzzle, legs/feet, occasionally trunk. Localized or generalizedLocalized or generalized Peripheral lymphadenopathy is common due to secondary infection.Peripheral lymphadenopathy is common due to secondary infection.

Demodex treatment Correct/treat underlying conditions Correct/treat underlying conditions Neuter/spay Neuter/spay Treat secondary bacterial infections Treat secondary bacterial infections Topical treatment Topical treatment Benzoyl peroxideBenzoyl peroxide Mitaban (Amitraz) dipsMitaban (Amitraz) dips Ivermectin SID Ivermectin SID Increasing oral doseIncreasing oral dose Mibemycin Mibemycin (interceptor SID)(interceptor SID) Continue treatment one month beyond a negative skin scrape. Continue treatment one month beyond a negative skin scrape.

Malassezia Dermatitis Yeast found in low numbers in the ear canal, peri-orally, peri-anally, and moist skin folds Yeast found in low numbers in the ear canal, peri-orally, peri-anally, and moist skin folds Almost always associated with underlying disease (atopy, food allergy, endocrine disorders) Almost always associated with underlying disease (atopy, food allergy, endocrine disorders) Common in dogs- rare in cats Common in dogs- rare in cats

Malasezzia continued Causes moderate to intense pruritis with regional or generalized alopecia. Causes moderate to intense pruritis with regional or generalized alopecia. Chronic changes: Chronic changes: HyperpigmentedHyperpigmented LichenificiationLichenificiation HyperkeratosisHyperkeratosis Odorous skin Odorous skin

Malassezia diagnosis Skin scrape and stain, skin imprint, tape prep Skin scrape and stain, skin imprint, tape prep Lesions may involve interdigital spaces, axillary region, neck. Lesions may involve interdigital spaces, axillary region, neck. Cytology reveals budding yeast (round to oval) Cytology reveals budding yeast (round to oval)

Malassezia treatment Correct underlying cause Correct underlying cause Shampoos Shampoos KetoconazolKetoconazol MiconazolMiconazol ChlorhexidineChlorhexidine In severe cases use systemic ketoconazole, iatroconazole In severe cases use systemic ketoconazole, iatroconazole