Small Ani. Med- Diagnostic approach to the pruritic cat 1 (Lecture 5+6)

drraythe's version from 2016-04-29 14:38

intro + Notoedric mange (ectoparasites)

Question Answer
Cats manifest pruritus in different ways....what are some examples?Scratching, Licking, chewing, Overgrooming / barbering, Rubbing, Seizure-like activity. Cats are Often secretive (“closet groomers”). **Many different clinical presentations for the same diseases
Clinical presentations (reaction patterns) of pruritic cats are... (4)(1) Facial pruritus with facial lesions: excoriations, crusts (2) Miliary dermatitis: crusted papules over dorsum (3) Symmetric truncal/flank/inguinal alopecia (4) Eosinophilic plaques, ulcers, granulomas
what does miliary dermatitis look like?crusted papules over dorsum
Differential diagnoses for pruritus in cats--> what are the 3 main categories, and what are subcategories which fit into them?(1) Ectoparasites (Notoedres cati, Demodex cati / gatoi, Cheyletiella, Fleas, Otodectes cynotis) (2) Allergic dermatitis (Flea allergy dermatitis, Atopic dermatitis, Food intolerance/allergy) (3) Infectious diseases (Dermatophytosis, Malassezia dermatitis (rare), Superficial pyoderma)
Notoedric mange is caused by?Notoedres cati
how contagious is Notoedres cati?Highly contagious, can affect any cat (Usually more than one cat affected in household)
Does Notoedres cati cause pruritus?Can cause intense pruritus (Hypersensitivity reaction)
how does notoedres cati mange live on the body?Female mite burrows into skin, then lays eggs (Can transiently infest dogs, people)
where does Notoedres cati live geographically?Very uncommon in N. America, common in Australia, certain parts of Europe
clinical signs of a notoedres cati infection? distribution of CS?Intense pruritus (9-10/10) which Typically affects head and pinnae (If chronic, entire body and feet). Also see Crusting, scaling, erythema, alopecia, 2o self-trauma, “seizure”. In severe cases, peripheral lymphadenopathy, anorexia, emaciation, death
will you see systemic signs with notoedric mange?In severe cases, peripheral lymphadenopathy, anorexia, emaciation, death
what are the two ways to dx notoedric mange?(1) Superficial skin scrapings (2) Response to treatment (i.e. if history is suspicious, do empirical acaricidal therapy)
is notoedric mange a deep or superficial skin scrape?SUPERFICIAL (they burrow in skin like scabies)
what Acaricidal Therapy do you use for tx notoedric mange?Selamectin or moxidectin! (q 2 weeks, 3 times). Can also try: Ivermectin, 2% lime sulfur, Amitraz. Treat all in-contact mammals!

Demodex species and Cheyletiellosis (ectoparasites)

Question Answer
what are the 2 possible species of feline demodicosis?Demodex cati, Demodex gatoi
how do you tell Demodex cati and Demodex gatoi apart on appearance?Cati has a super long tail (cats have long tails)
where does demodex cati usually like to live? When do you see D. Cati?Normal commensal of the skin. Usually only seen in very sick cats (Metabolic disease, Immunosuppressive disease)
is D. cati pruritic? is D. gatoi?D. Cati is NON-PURITIC. D. gatoi can be none to MARKED ((so Cati should not cause pruritus under any conditions- makes sense bc they are a commensal)
what are lesions/ distribution of lesions like for D. Cati?Non-pruritic condition!!! Patchy, regional, multifocal alopecia which can be Can be localized or generalized (very rare condition)
which is contageous- D. cati or D. gatoi?D gatoi (remember Cati is a commensal)
what are the lesions/ distribution of lesions for D. gatoi?Pruritus – none to marked and found in thestratum corneum (uppermost layer)-- normal habitat unknown
where is D. gatoi most often found geographically?In the US, most frequently encountered in the south
what are the clinical signs of feline demodicosis?Variable pruritus; none to marked (Cati is non-pruritic) Alopecia (Focal, patchy, generalized, symmetrical), +/- erythema, crusts, scales, +/- secondary pyoderma, +/- ceruminous otitis externa
how do you dx feline demodicosis? (4)(1) Superficial skin scrapings (Non-affected cats should also be scraped- if you can't find them on the itchy affected cat, you might be able to find them on a clinically unaffected cat) (2) Acetate tape test (3) Fecal floats* (might ingest them when grooming) (4) Empirical treatment and response to lime sulfur dips
deep or superficial scrape for feline demodicosis?SUPERFICIAL!!! these guys live superficially unlike the dog ones!!
what are two treatments for feline demodicosis?(1) Lime sulfur dips (2-4%) (1-2 times per week for 2 months) (2) Amitraz dips (Anorexia, lethargy, diarrhea)
which type of demodex can resolve spontaneously in cats?D. cati can resolve spontaneously if underlying disease is addressed (bc normal commensal that just gets out of control due to immunosuppression)
Cheyletiellosis is caused by?Cheyletiella blakei (aka Walking dandruff, rabbit fur mite)
where do cheyletiella like to live on the cat?Live on hair, feed on skin- Very superficial!
is cheyletiella contagious?HIGHLY contagious
clinical signs of Cheyletiellosis?Scaling/crusting*, Miliary dermatitis, "Walking dandruff", Primarily a disease that causes ****dorsal lesions*, Pruritus is absent to severe
does Cheyletiellosis have pruritus?absent to severe
what should you warn owners about cheyletiellosis?possible zoonosis!!
how do you tx Cheyletiellosis? (5)Acaricidal therapy! (1) Selamectin or moxidectin (q 2 weeks, 3 times) (2) Ivermectin (3) 2% lime-sulfur (4) Amitraz (5) Milbemycin oxime......dont forget to Treat all in-contact mammals

Dermatophytosis (Infectious diseases)

Question Answer
what is Dermatophytosis?Superficial fungal infection of hair shafts and stratum corneum. Proteolytic / keratolytic enzymes allow keratin to be used as nutrition
how are dermatophytes transmitted?Transmission by direct-indirect contact
what are the 3 species of dermatophytes which affect cats? which is the most common one in cats?Microsporum canis (zoophilic) (*most common- 98% of the time. common but should not be considered a normal flora), Microsporum gypseum (geophilic), Trichophyton mentagrophytes (zoophilic)
what 3 populations of cats are esp sensitive to dermatophytes?(1) Young , immunocompromised (2) Cats with skin trauma (Pruritus, playing / fighting, ectoparasites, clipping, Poor hygiene, "social stress" (3) Asymptomatic (subclinical) carriers (Long-haired cats, Persians)
Which cats tend to be asymptomatic carriers of dermatophytes?Long-haired cats, Persians
what are the clinical signs of dermatophytosis?(Many different presentations!) Circular areas of alopecia with erythematous border, Transient follicular pustules, Miliary dermatitis, Scale/crusts absent to severe, Rarely, dermal nodules (pseudomycetoma), Pruritus variable
what is a pseudomycetoma?dermal nodules, rarely a clinical sign of dermatophytosis
5 ways to dx dermatophytes?(1) Wood’s lamp examination (****REMEMBER: Only 50% of M.canis will fluoresce) (2) Trichogram (3) Dermatophyte PCR (4) Fungal culture and ID (Sabouraud’s agar) (5) Biopsy + special stains (PAS)
which stain would you stain a dermatophyte bx with?PAS
*woods lamp only works when?Only 50% of M.canis will fluoresce!
easy way to collect sample for culture?brush cheap toothbrush over lesions and over non-lesioned areas, dip toothbrush in culture medium, send it away
what is the culture medium you use to grow dermatophytes? what is in the culture medium?(can be plain Sabouraud’s agar also) Dermatophyte test medium (DTM) which contains Antibiotics (Gentamicin, chlortetracycline), Cycloheximide, Phenol red, Carbohydrate and protein nutrients
how does DMT medium encourage dermatophytes to grow, as opposed to saprophytes which are just around and in the air? What is a color change which helps indicate growth?Dermatophytes use protein as energy first vs. saprophytes which use carbs. DMT has protein nutrients in it. Also, DTM changes from yellow to red due to production of alkaline by-products
what are you looking for with the DMT culture for your dermatophytes? (3 things you do)(1) Check sample daily to observe yellow to red colour change (2) Assess growth colony macroscopically (White, buff, tan) (3) Assess growth colony microscopically (more on this in diff card)
what colors of colonies are you looking for when culturing dermatophytes on DMT?white buff and tan
how do you Assess growth colony microscopically (how do you get a sample? what stain? what should Macroconidia of M. canis look like?)use tape to gather a sample from the growth medium, and stain with blue modified Wright’s stain (Diff quik #3). Macroconidia of M. canis should have >6 cells with thick cell walls and knobs on their ends
what are the Principles of Treatment for dermatophytes? (4) (when can you stop treating is one of them)(1) Identify all affected animals/subclinical carriers (2) Quarantine all affected (3) Treat until 2 consecutive negative fungal cultures, 2 weeks apart (4) Environmental decontamination
how do you know when to stop tx for dermatophytes?Treat until 2 consecutive negative fungal cultures, 2 weeks apart
what are 4 options for topical therapy for dermatophytes?Lime sulfur dips, Enilconazole spray, Miconazole 2% shampoo, Terbinafine cream (Lamisil®) (Not always effective as sole therapy)
what should you warn owners about lime sulfur dips as a topical tx for dermatophytes?Will stain white cats, Smells awful, Remove silver jewelry or it will be tarnished
what are three options for systemic tx of dermatophytes? what should you NOT USE for tx cats with dermatophytes?CAN USE: Itraconazole/fluconazole 7-10mg/kg/day PO with food. OR Terbinafine 40mg/kg PO q 24h. DO NOT USE: Cats do not tolerate ketoconazole~ --> GI upset, hepatotoxicosis
4 things you can do to help reduce environmental contamination of dermatophytes?(1) Daily cleaning with dilute bleach 1:10 for all hard surfaces (2) Change air filters (3) Throw away anything that may harbour spores (4) Steam clean carpets, drapes, wash bedding

Flea allergic dermatitis (FAD) + Cutaneous adverse food reaction (CAFR) (Allergic dermatitis)

Question Answer
4 main clinical signs of FAD?(1) Pruritus (2) Self-induced alopecia (Typically neck, back, lumbar skin) (3) Papules, miliary dermatitis (4) Eosinophilic dermatoses
where does self-induced alopecia from FAD tend to distribute?Typically neck, back, lumbar skin
common history of FAD cats?Seasonal or year-round pruritus, Introduction of new pet, Flea control absent or inadequate, lifestyle
clinical signs of FAD?Pruritus, any distribution, Eosinophilic dermatoses (any manifestation), Presence of fleas, flea dirt (Absence does not rule out FAD)
the three objectives to treating FAD are...(1) Complete flea eradication in the environment (2) Provide symptomatic relief (3) Treating and preventing infestations
4 Flea adulticides you can use to tx FAD(*remember: SPEED OF KILL IS IMPORTANT!! IT is the BITING that is the problem!) Capstar (nitenpyram), Revolution (selamectin), Comfortis (spinosad), Cherestin (spinetoram)
what are 2 types of tx you should NOT be using to tx cats with FAD?(1) Using IGRs to manage FAD is not appropriate! (2) Dog products can be toxic to cats (pyrethrins, pyrethroids)
Cutaneous adverse food reaction--> what kinda hypersensitivity reaction?Type I, III, IV hypersensitivity reaction
Cutaneous adverse food reaction--> Common allergens in catsFish, beef, chicken, dairy, soy, corn, wheat
how often is a recent change in diet a precipitating factor in cutaneous adverse food reaction?Recent change in diet uncommon (bc often need time to develop reaction)
4 main CS of CAFR?(1) Pruritus *Face/neck in 40-50% of cases (2) Self-induced alopecia- can be Focal, generalized, bilaterally symmetrical, regional (3) Miliary dermatitis (4) Eosinophilic dermatoses
where does the pruritus for CAFR often present?*Face/neck in 40-50% of cases
Cutaneous adverse food reaction--> what other clinical signs are concurrent in 10-20% of cases?Vomiting, diarrhea
If you see GI signs and pruritus, what do you think is going on?food allergies!
how do you dx CAFR?As in dogs, must perform elimination diet trial. You can try Novel protein diet, hydrolyzed diet, or home-cooked diet for 8 weeks (Some dermatologists recommend 10-12 week trial)
what is the average length of a elimination diet trial?8 weeks (some Drs recc 10-12wks)

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