Feline Dermatology Flashcards
T/F: in cats you cant use historical and distribution of lesions as much as you can in dogs
True
T/F: preauricular alopecia is a normal finding in cats
True
What are some normal dermatology findings in cats
-Preauricular alopecia
-Lentigo (lentigines)
What is lentigo
black spots seen in orange cats
single or multiple
on lips, eyelids, gingiva, pinnae, nasal planum
What kinds of cats typically get lentigo (lentigines)
orange cats
Where do orange cats typically get lentigo
on lips, eyelids, gingiva, pinnae, nasal planum
normal finding
What might an itchy cat look like
excessive grooming
-increased hairballs
-lick/bite/chew/scratch
hiding
really whatever
miliary dermatitis in cats is a
reaction pattern associated with pruritus in cats
What does miliary dermatitis look like in cats
Crusted papular eruption
focal or generalized
easier to feel than to see
What is non-inflammatory alopecia in cats
“Bald belly” syndrome
truncal / bilaterally symmetrical
limbs
caudal half of body
may be no obvious skin lesions
What are some reaction patterns associated with pruritus in cats
1) Miliary dermatitis
2) Non-inflammatory alopecia
3) Eosinophilic granuloma complex
need to do systemic work up to see why they are itchy
What might cause traumatic feline alopecia
-Flea bite hypersensitivity
-Environmental allergy (atopy)
-Food sensitivity
-Secondary bacterial pyoderma
-Dermatophytosis
-Contagious ectoparasitism
-Demodicosis
-Malassezia (secondary)
-Underlying irritation (eg cystitis)
-Hyperthyroidism
-Psychogenic alopecia
Before diagnosing Psychogenic alopecia, you need to do
rule out every single cause of pruritus and skin disease
How do you distinguish traumatic alopecia from a non-inflammatory alopecia
Trichogram
normal (non-inflammatory): tapered edge
Traumatic alopecia: hair looks ripped off
eosinophilic infiltrate within the skin and/or oral cavity
not a diagnosis but a clinical syndrome (reaction pattern)
Eosinophilic granuloma complex
What are the 3 lesion types of the Eosinophilic granuloma complex
1) Eosinophilic granuloma
-Linear granuloma
-Oral granuloma
-Interdigital granuloma (uncommon)
2) Eosinophilic plaque
3) Indolent “rodent” ulcer
What is fat chin syndrome
a eosinophilic granuloma
How do you differentiate eosinophilic plaque from granuloma or nodule
plaques are raised and flat topped
Eosinohphilic plaques like to appear where
on the caudal thigh
If you were to biopsy an eosinophilic plaque, what would you see?
eosinophils and pyogranulomatous inflammation
Eosinophilic granulomas tend to predominately what on biopsy
pyogranulomatous
What are the types of eosinophilic granulomas
Linear granuloma
Oral granuloma
Interdigital granuloma (uncommon)
T/F: indolent ulcers can be unilateral or bilateral
True
Why do eosinophilic granuloma complex resolve with antimicrobial therapy
not sure why they respond to antibiotics
maybe antiinflammatory properties
dont just give every one antibiotics - do a proper workup
What causes pruritus in cats
PAIN
Parasites
Allergy
Inflammation
Neoplastic, neurogenic
What are differential diagnoses for pruritus in cats
1) Dermatophytosis
2) Ectoparasites
3) Allergy disease - flea allergy dermatitis, food allergy, atopy, non-flea/noon-food hypersensitivity
4) Pemphigus foliaceus
5) Mosquito bite hypersensitivity
6) Herpesvirus dermatitis
What is the most common species of Dermatophytosis in cats
Microsporum canis
T/F: Dermatophytosis in cats is variably pruritic
True
What are the 4 causes of allergic disease
1) Flea allergy dermatitis
2) Food allergy
3) Atopy
4) Non-flea, non food hypersensitivity (NFNFHD)
T/F: pemphigus foliaceus is variably pruritic in both dogs and cats
True
What diagnostics do you do for feline alopecia
1) Flea examination /comb
2) Minumum databse
3) Cytology
-Superficial / Deep Skin scrapes
-Acetate tape (Dry lesions/scale)
-Impression smear (exudative)
-Woods Lamp
-Fungal culture/PCR
if negative- biopsy? trial treatment??
Why is it harder to find live fleas and dirt on cats
Because they are groomers
What are the most common allergy in cats
Flea allergy (but varies by location)
What are types of ectoparasites that affect cats
1) Demodex gatoi
2) Demodex cati
3) Otodectes cynotis
4) Notoedres cati
5) Cheyletiella spp
How is demodex gatoi different from other Demodex
Superficial mite
in the stratum corneum
hard to find
Where does demodex gatoi live
Stratum corneum (hard to find because cats are good groomers)
-Consider fecal float, trichogram
T/F: demodex gatoi is associated with immunosuppression
False
What is the sarcoptes of cats
Notoedres cati
What are the characteristics of Demodex gatoi
1) Lives superficial (stratum corneum)
2) Pruritic
3) Short, fat body
4) Contagious **
5) Not associated with underlying immunosuppression
What demodex species in cats is contagious and not associated with underlying immunosuppression
Demodex gatoi
What do you see with the localized form of demodex cati
most common - usually self limiting
nose, periocular skin, neck
variable pruritus
alopecia, erythema, crusting, hyperpigmentation
ceruminous otitis
may be ears only
What might be the only sign of demodex cati
Ceruminous otitis
What do you see with the generalized form of demodex cati
same clinical signs as localized: alopecia, erythema, crusting, hyperpigmentation
ceruminous otitis
head, neck, trunk, limbs
Concurrent systemic disease: FeLV/FIV, diabetes mellitus, neoplasia, hyperadrenocorticism, toxoplasmosis
What are the concurrent systemic diseases associated with generalized demodex cati
FeLV/FIV, diabetes mellitus, neoplasia, hyperadrenocorticism, toxoplasmosis
What is the feline scabies
Notoedres cati
-contagious
What do you see with Notoedres cati
heavily crusted head and neck
contagous
How do you diagnose Notoedres cati
Superficial skin scrape
How do you diagnose Demodex cati
Deep skin scrape
How do you diagnose Demodex gatoi
Superficial skin scrape , fecal float, trichogram
T/F: food allergy in cat is often steroid responsive
False
What will you see in food allergy in cats
Head neck pruritus common (nonseasonal)
may be intense
Why are diet trails challenging in cats
Fewer options
Finicky eaters
Is atopy more common in dogs or cats
Dogs
T/F: Atopy in cats can be seasonal or nonseasonal
True
How do you diagnose atopy in cats
diagnosis of exclusion
IDAT-rewarding? not really
steroid responsive
Why is IDAT testing less rewarding in cats
1) More reactive - will need general anesthesia
2) Cats dont produce reliable and consistent hives
*Cant inject IV fluoroscein dye to help
Do serology instead for atopy
What helps with Atopy in cats
Steroid responsive
Atopica- consider risks and lifestyle
What is the distinct sign of Insect hypersensitivity in cats
Mosquito bites on bridge of nose, pinnae, footpads
What are the only areas affected by mosquito bite / insect hypersensitivity in cats
1) Bridge of nose
2) Pinnae
3) Footpads
What are the two types of paraneoplastic alopecia in cats
1) Hepatic/biliary/ pancreatic carcinoma / adenocarcinoma
-Alopecia, seborrhea, shiny skin
2) Thymoma
-Exfoliative dermatitis
-Alopecia, severe seborrhea, generalized erythema +/- claw fold involvement
What might the skin look like if the cat has Hepatic/biliary/ pancreatic carcinoma / adenocarcinoma
Alopecia, seborrhea, shiny skin
How do you diagnose paraneoplastic alopecia
Take A Biopsy
Abdominal imaging (Hepatic/biliary/pancreatic carcinoma or adenocarcinoma)
Thoracic imaging (Thymoma)
What might the skin look like if the cat has a thymoma
-Exfoliative dermatitis
-Alopecia, severe seborrhea, generalized erythema +/- claw fold involvement
Psychogenic alopecia is a diagnosis of
exclusion
only 2/21 cats has alopecia determined to be entirely psychogenic
3/21 has psychogenic component combined with a dermatologic problem (food allergy and/or atopy)
In cats, how do you treat allergic dermatitis
Food trial
Therapeutics
Immunotherapy
In cats, how do you treat infectious alopecia
Topical/systemic antibiotics
Fungal - imidazoles, terbinafine
How do you treat ectoparasite caused alopecia in cats
Isoxazoline, avermectins, fipronil
What are the type of antihistamines in cats
Chlorpheniramine, cetirizine, amitripytline, clemastine
about 15-20% response rate (only for mild or combination therapy)
What can you do for steroid treatment of allergy
1) Prednisolone / methylprednisolone: 1-2mg/kg/day/ 0.5mg/kg EOD long term
2) Triamcinolone acetate PO, Dexamethasone PO
0.1-0.2mg/kg day
3) Depo steroids
Methylprednisolone acetate (DepoMedrol)
Triamcinolone acetonide (Vetalog)
minimum 6-8 weeks between injections
When starting cats on prednisolone/methylprednisolone. What dose should you use
Start 1-2 mg/kg/day then go to 0.5mg/kg EOD-long term
this is still anti-inflammatory dose for cats
If a cat is no longer susceptible to Prednisolone for allergy, what should you try
Triamcinolone acetate or Dexamethasone
go 5-7 days then taper
There should be a minumum of __________ weeks between injections of Methylprednisolone acetate (DepoMedrol) or Triamcinolone acetonide (Vetalog) **
6-8 weeks Minimum
Why do cats need higher doses of steroids
Fewer receptors
Cats more resistant to common side effects in dogs
What are the most common side effects of steroids in cats
Diabetes mellitus (insulin resistance)
Skin fragility, curling of tips of ears, exacerbation of underlying heart disease
What is best for long-term management of pruritus in cats
Atopia - slow onset (takes 1 month to work)
What might be considerations on not using Atopia
Outdoor or indoor cats
do retrovirus testing
T/F: maropitant may be a useful antipruritic therapy in cats
True
Why is Apoquel not commonly used in cats
1) Off-label use
2) metabolized more quickly in cats (higher doses and dosing intervals
3) Lower bioavailability
does appear safe tho - requires monitoring
Apoquel is not commonly used in cats, but what is the dose
1mg/kg BID
try reducing to approx 0.5mg/kg BID once clinical control is achieved
T/F: Immunotherapy is used for diagnosis
false - it is even more difficult to interpret in cats
might consider serology
What should you do for bacterial pyoderma in cats
often gram + (Staph)
do 3-6 weeks (superficial/deep)
topical?
do cytology
What do you do for Malassezia in cats
Imidazoles - Itraconazole, Terbinafine
3-6 weeks (superficial/deep)
cytology is important
What does malassezia look like in cats
Seborrha oleosa
How do you diagnose dermatophytosis in cats
Fungal culture/ PCR
How do you treat dermatophytosis in cats
Itraconazole, terbinafine
topicals helpful
do environmental cleanup
focal abnormality of keratinization / possibily lipid production (comedo formation)
Feline acne (cornficiation disorder)
What is a common progression of feline acne
furunculosis
What are some theories behind feline acne
Poor grooming
Hormonal influences (androgens)
Stress
Viral infection (group outbreak)
Reaction to food bowl (plastics)
allergy
no one really knows
What does feline acne look like
comedones
papules, pustules, crusts, furunculosis
What are differentials for feline chin acne
really anything
-atopy
-food sensitivity
-bacterial pyoderma (secondary)
-Malassezia (secondary)
-Dermatophytosis
-Demodicosis
-Pemphigus foliaceus
How might you work up feline chin acne
1) Cytology - impression smears (exudative), acetate tape (dry lesions)
look for bacteria, Malassezia
2) Deep skin scrape +/- trichogram for demodex
3) Dermatophyte culute/ PCR +/- Woods Lamp for dermatophytosis
What should you do for mild to moderate feline acne
1) Nothin (benign negletc)
2) Dermoscent feline: topical fatty acids 2x weekly
3) Douxo Calm gel/spray: Phytoshingosines q24h to BID
4) Shampoo (as necessary)
-Seborrhea shampoons like sulfur/salicyclic acid, Benzoyl peroxide
What should you do for moderate to severe feline acne
1) Mupirocin (topical antibiotic)
BID to 2-3 weeks then q24h
mild controversy
2) Oral or injectable antibiotics with gram + spectrum
3) +/- systemic steroid like 1-3mg/kg prednisolone for 2-3 weeks
If severe - maybe debridement surgically? but make sure you resolve other factors first
What is the distribution of pemphigus foliaceus in cats
typically at the face- nasal planum, pinnae, periocular skin
can go generalized
perinipular and peronychia
What causes pemphigus foliaceus in cats
most are idiopathic
some can be drug-induced (resolve with discontinuation)
some can be drug-triggered (persist after discontinuation)
What cat ages are affected by pemphugys foliaceus
1-17 years (average 6 years)
What is the distribution of pemphigus foliaceus in cats
Head/face, face
footpads
nail folds
Peri-aeroeolar
may become more generalized
What drugs might trigger pemphigus foliaceus in dogs and cats
Penicillins
Cephalosporins
Sulfa (TMS)
NSAIDS (ie carprofen)
Phenobarbital
any drug can cause adverse effects though
What is the pathogenesis of pemphigus foliaceus
Auto-Antibodies against desmosomes
see acantholytic keratinocytes
What are differentials for paronychia
Pemphugus foliaceus
Dermatophytosis
Bacterial pyoderma
Malassezia
Metastatic bronchogenic carcinoma
What can you do for pemphigus foliaceus diagnostics
1) Cytology - neutrophils/eosinophils, acantholytic keratinocytes, secondary infection is possible, beware Staph/dermatophytes
2) Biopsy (definitive) on pustules (transient) or crusts
What can you do therapeutically for cats with pemphigus foliaceus
1) Prednisolone: 2-3mg/kg/day generally two weeks to remission
2) Triamicinolone (preferred by some): 0.2 to 0.3mg/kg/day
3) Dexamethasone: 0.2-0.3 mg/kg/day
4) Cyclosporine (Atopica): 5-10mg/kg/day once controlled with steroids
5) Chlorambucil
6) Adequan?
want to reduce steroid dosing to few times a week
What 3 things cause acantholytic keratinocytes
1) Bacterial pyoderma
2) Dermatophytosis
3) Pemphigus foliaceus
In order to diagnose pemphigus foliaceus and the only sign is paronychia, what might you do or dont do
Amputate P3
What causes plasma cell pododermatitis in cats
unknown - immune mediated? allergic? FIV association
What does plasma cell pododermatitis look like in cats
Pads are puffy, soft, white striations, deflated, purple hue, mushy pads
+/- ulceration
metacarpal / metatarsal pads most commonly affected (1-4 feet)
variable pain/lameness
may wax and wane
Are males or females predisposed to plasma cell pododermatitis
Males
plasma cell pododermatitis can affect how many feet
1-4 feet
What systemic signs might you see with plasma cell pododermatitis
pyrexia, lethargy, anorexia, peripheral lymphadenopathy, stomatitis, may be lame
How do you diagnose plasma cell pododermatitis in cats
Cytology (FNA)
Biopsy (do under general anestheisa)
See plasma cells
What two sites should you have the animal under general anesthesia when you are biopsying
1) Nasal planum
2) Paw pads
very sensitive and hard to get local anesthesia in
What bloodwork changes might you see with plasma cell pododermatitis
Hyperglobulinemia - very common
Proteinuria (glomerulonephritis) - uncommonly
some may have thrombocytopenia
How do you treat plasma cell pododermatitis
1) Spontaneous resolution possible
2) Doxycycline- remission in majority within 30-90d
watch tablets (strictures), watch compounded (expiration)
3) Prednisolone
4) Oral triamcinolone or dexamethasone
5) Cyclosporin
6) Surgical excision- especially sites of hemorrhage or severe proliferation
ceruminous cysts that typically occur at the pinna, external orifice, occassionally ear canal in cats
Ceruminous cystomatosis
Ceruminous cystomatosis in the ear canal mght be initiated by
otitis externa
may also cause otitis externa and ear canal obstruction
Ceruminous cystomatosis might cause what in cats
1) Otitis externa
2) Ear canal obstruction
How do you diagnose Ceruminous cystomatosis
really all you need is visual but can do FNA or biopsy
What can you do for Ceruminous cystomatosis
laser ablation
topical glucocorticoids
surgery (ablation?)
cryosurgery
lance/silver nitrate
What cat breeds typically get idiopathic facial dermatitis
Persians and Himalayans (flat faced)
seborrhea oleosa of the face of cats
usually pruritic
idiopathic facial dermatitis
How do you diagnose idiopathic facial dermatitis in cats
clinical signs, signalment, cytology (secondary infection)
How do you treat idiopathic facial dermatitis in cats
treat secondary infections or topical tacrolimus
What does herpesvirus facial dermatitis in cats look like
typically ulcerative lesions
upper respiratory signs concurrently or previous
How do you treat herpesvirus facial dermatitis
supportive, L-lysine, interferon
Topical acyclovir treatment of choice**
+/- steroid responsive
What is the treatment of choice for herpesvirus facial dermatitis **
Topical acyclovir
What will you see on cytology of herpesvirus facial dermatitis
Eosinophils with no peripheral eosinophils
+/- secondary infection
How do you distinguish eosinophilic granuloma complex vs herpesvirus facial dermatitis on cytology
both have lots of eosinophils but herpesvirus facial dermatitis has no peripheral eosinophilia
EGC will have peripheral eosinophilia
What dermatologic changes are seen with FeLV
1) Cutaneous horns - especially on the foodpads
2) Recurrent pyoderma or demodicosis
3) Neoplasia - lymphoma
With FeLV, where do you typically see the cutaneous horns **
the foodpads - cutaneous growth of keratin
if you see cutaneous horns- do retovirus testing
