Feline Dermatoses Flashcards
What is preauricular alopecia? What is the significance?
- Alopecia that is normal and located in the preauricular area in cats
- Very noticeable in black cats
Describe the appearance and distribution of lentigines?
- Pigmented macules or patches on orange cats due to increased melanocytes and melanin
- Nasal planum, eyelids, lips, gingiva, pinnae
Significance of lentigines?
- Coalesce and increase with age
- Benign!
How common are feline dermatoses relative to canine?
- Less common
How common is true folliculitis (pyoderma) and secondary infections (yeast dermatitis) in cats?
- Less common
Are historical details and location of pruritus as consistent with felines?
- No
What are reaction patterns?
- Reactions that commonly develop secondary to an antigenic stimulus from either allergies or ectoparasites
- Can also be seen with infectious caues such as ringworm though
What is the systematic diagnostic approach to cats?
- FeLV/FIV status
- Rule out dermatophytes
- Rule out flea allergy, etc.
How do cats manifest pruritus?
- Scratching
- Biting
- Excessive grooming (hairballs)
- Hypotrichosis
- Alopecia
- Hiding
What virus can be associated with intense pruritus?
- Herpes
What should you check with a non-healing wound in a cat?
FeLV/FIV status
What are three feline reaction patterns you should absolutely know?
- Miliary dermatitis
- Alopecia
- Eosinophilic granuloma complex
Describe miliary dermatitis
- Small, multifocal crusts
- Crusted papular eruption
- Can be focal or generalized
- Can feel with palpation
Differentials for miliary dermatitis
- Allergies (flea, food, atopy, insect)
- Ectoparasites (Notoedres, Cheyletiella, D. gatoi)
- Infectious (Dermatophyte, Pyoderma, Malassezia)
Alopecia appearance with cats
- Bald belly but often no skin lesions
What diagnostic test should you do with “bald belly” in a cat, and what is it telling you?
- Trichogram to determine if hair is falling out or being removed
Dfdx for “bald belly” or alopecia
- Allergy (flea, food, atopy)
- Ectoparasites (Cheyletiella, D. gatoi)
- Infectious (dermatophyte)
What is an eosinophilic granuloma complex?
- Eosinophilic infiltrate
- Antigenic stimuli
- Hypersensitivity reaction
What are common underlying causes for eosinophilic granuloma complex (since it’s NOT a diagnosis)?
- Allergies, hypersensitivities, and ectoparasites are common underlying causes
What are the three syndromes associated with eosinophilic granuloma complex?
- Indolent ulcer
- Eosinophilic plaque
- Eosinophilic granuloma
Describe an eosinophilic plaque?
- Alopecic
- Erythematous raised plaques, erosions, or ulceration**
- Pruritic
- Abdomen and thighs
- often moist and oozing
Describe an indolent ulcer
- Rodent ulcer
- Upper lip
- Unilateral or bilateral
- Non-painful
- Can become disfiguring
What are four types of eosinophilic granulomas
- Linear granuloma
- Oral granuloma
- Interdigital granuloma
- Pouty lip or fat chin syndrome
Location of eosinophilic granulomas?
- Caudal aspect of rear legs, chin, axilla
Clinical signs of most eosinophilic granulomas?
- Usually asymptomatic
Describe linear granulomas (appearance, location, pruritic or not)?
- Linear conformation
- Yellow or pink nodules
- Caudal thighs, chin, axilla
- Not pruritic
- Discovered incidentally
Describe oral granuloma appearance, and where do they show up?***
- Hard or soft palate
- Tongue
- Nodular looking thing
Describe interdigital granuloma
- Can be asymptomatic or clinical
- Nodular or ulcerative masses in-between the digits
Rule outs for feline allergy?
- Flea
- Food
- Atopy
- Insect
What is the most common allergy in cats?
- Flea allergy
Seasonality of flea allergy in cats?
- Can be seasonal or non-seasonal
Clinical signs of FAD?
- Any eosinophilic granuloma complex lesions
- Itching
- OVergrooming
Which flea causes FAD in cats?
- Ctenocephalides felis
Can flea allergy happen even if:
Cat is indoor or outdoor?
No fleas seen?
Flea control?
- YeS
Pathogenesis of FAD
- Antigen in saliva
- Type I and IV
- Hypersensitivities
Diagnosis of flea allergies in cats
- Flea comb may or may not be helpful (negative doesn’t rule it out)
- Fecal (tapeworms support)
- Response to therapy (treat secondary infections; capstar trial every other day for 30 days; or bravecto)
- Rule it out in every pruritic cat
Treatment for flea allergy
- Strict, year-round flea control
- Topical adulticide (Bravecto or Revolution)
- Flea control for all in-contact animals (Revolution)
- +/- treat environment (Lufenuron; environmental treatment)
What is the second most common allergy in cats?
- Food allergy
Reaction patterns possible with food allergy
- Any
- Any eosinophilic granuloma complex lesions
- Recurring otitis
Seasonality of food allergy in cats
- Non-seasonal
Age of cat with food allergy
- Often <1 year
Distribution of pruritus in cats with Food allergy
- Head and neck pruritus common
Concurrent signs with food allergy in cats
- 10-30% have concurrent GI signs
Which proteins are cats allergic to most commonly?
- Chicken
- Beef
- Dairy
- Fish
Pathogenesis of food allergy in cats
- Largely unknown
- Allergen in most cases is a protein
Diagnosis of food allergy in cats
- Food trial (novel protein vs hydrolyzed diet)
- 6-8 week minimum
- STRICT
- At the end, challenge with original diet
- Treat with any secondary infections
Serum allergy tests for food allergy
- Not reliable
Which diets are appropriate for a food trial?
- RC rabbit
- RC ultamino
- RC HP
Seasonality of feline atopy
- Seasonal or non-seasonal pruritus
Reaction patterns possible with feline atopy
- Any reaction pattern
- Any eosinophilic granuloma complex lesiosn can be seen
Pathogenesis of atopy in cats
- Inhaled and cutaneously absorbed allergens
- Type I hypersensitivity
How to diagnose atopy in cats?
- Rule out flea and food allergies first (Bravecto or Revolution or advantage multi every 2 weeks for 3 consecutive treatments)
- treat for ectoparasites
- Diagnose infections
- Atopica trial
Treatment for atopy
- Antihistamiens
- Glucocorticoids
- Atopica
- Allergy specific immunotherapy
- Bathing?
- Free fatty acids?
Antihistamines for cats with Atopy
- Chlorpheniramine (mediocre)
- Amitriptyline (also psychotropic)
- Cetirizine (Zyrtec)
Atopica trial for cats with atopy
- Cyclosporine
- Approved for use in cats
What needs to be done before atopica trial in cats?
- Baseline bloodwork
- FeLV/FIV
- Dermatophyte culture!
Steroids for atopy in cats
- Prednisolone EVERY other day
- maybe more effective in ats?
Which insect is most responsible for insect hypersensitivity?
- Mosquitoes
Lesions associated with insect hypersensitivity
- Papules, pustules, crusts
WHere are lesions associated with insect hypersensitivity?
- Bridge of the nose, outer pinnae, footpads
Pruritus associated with insect hypersensitivity?
- Mild to severe pruritus
Diagnosis of insect hypersensitivity
- CLinical signs
- Outdoors at dusk
Therapy for insect hypersensitivity
- Indoor only
- Restrict access to outdoors at dusk
- Insect control
- Steroids
What should you do with pruritic ectoparasites?
- Always consider
- Always rule out
Appearance of Notoedric mange in cats
- Rare with endemic foci
- Pruritus of head and neck
- Crusting of head, ears, feet, perineum
How to diagnose Notoedres in cats?
- Superficial scrape
Notoedres cati characteristics: Contagious or not? Zoonotic or not?
- Contagious AND zoonotic
Etiology and appearance of Cheyletiellosis
- Cheyletiella blakei
- Large saddle-shaped with ACCESSORY MOUTH PARTS
- Walking Dandruff
How common is Cheyletiella?
- Not common anymore
Is Cheyletiella contagious? Zoonotic?
- Contagious and zoonotic
Treatment of Notoedres
- Treat all in-contact animals
- Bravecto
- REvolution/Advantage Multi every 2 weeks for 3 consecutive treatments
- Lime sulfur
- Ivermectin
Cheyletiella clinical signs
- Scale along the dorsum
- miliary dermatitis
- ALopecia (symmetrical)
- Pruritus
- Asymptomatic carriers are possible too
Diagnosis of Cheyletiella
- Not always easy
- SUperficial skin scrape
- Acetate tape prep
- Fecal
- Flea comb
- vacuum technique (hook up to a vacuum and collect)
- Response to treatment***
Treatment of Cheyletiella
- All in-contact animals
- This mite is easy to treat
- Frontline works
- Bravecto
- Revolution
- Advantage Multi
- Lime sulfur dips
Demodex gatoi
- Refer to notes on feline demodicosis
- Lime sulfur or bravecto?
Infectious causes of pruritus
- Dermatophytosis and Pyoderma
What must you rule out before using medications like steroids or atopica?
- Need to know if the cat has dermatophytosis
- Refer to notes
What are common underlying causes of pyoderma?
- True bacterial folliculitis is uncommon as compared to dogs
- Secondary infection to underlying allergies or ectoparasites
- Treat/address the same as in dogs
How common is psychogenic alopecia?
- Very uncommon
- Most (>80%) have above causes
Which breeds are overrepresented with psychogenic alopecia?
- Asian breeds overrepresented
Clinical signs of psychogenic alopecia?
- alopecia but no lesions
How to diagnose psychogenic alopecia?
- Diagnosis of exclusion by ruling out other potential causes of alopecia
Treatment of psychogenic alopecia
- Identify and eliminate possible stressors
- Psychotropic medications
- Amitriptyiline
Otodectes etiology
- Otodectes cynotis
Common clinical signs of otodectes?
- Otitis
- Pruritic dermatitis of the head and neck
Treatment for superficial mites (Notoedres, Cheyletiella, Otodectes)?
- Bravecto
- Revolution
- Advantage Multi
- Ivermectin
- Lime sulfur dips
Where does D. gatoi live?
- Stratum corneum
Appearance of D. gatoi
- Short, fat bodied mite
Is D. gatoi contagious?
- Yes
Diagnosis of D. gatoi
- Broad superficial scrapes (tough to find; between shouldre blades; scrape in contact animals)
- fecal
Treatment trial for D. gatoi
- Lime sulfur dip
- At least 6 dips
- All in contact animals if improvement is seen
Other differentials for cats with skin lesions
- Dermatophytosis
- Autoimmune
- Neoplasia
- Paraneoplastic
- Psychogenic
Which species of dermatophyte is most common in cats?
- Microsporum canis
Reaction pattern seen with M. canis?
- Miliary dermatitis
How to diagnose pyoderma and malassezia in cats?
- Cytology
Treatment for pyoderma in cats
- Topicals
- Oral abx like cephalosporins
- Injectable Convenia
Treatment for Malassezia in cats
- Topicals
- Oral antifungals (fluconazole, terbinafine)
Treatment of psychogenic alopecia
- Identify and limit stress
- Behavior modifying drugs
Diagnostic approach to pruritic cat: Step 1
- Derm data base for EVERY case
- Fungal culture (+treat for dermatophyte)
- SKin scrape (+ treat for mites)
- SKin cytology (bacteria or yeast treat secondary infections; eosinophils work up for allergy)
Diagnostic approach to pruritic cat: Step 2
- Rule out FAD and ectoparasites
- Strict flea control (Bravecto; Revolution/Advantage Multi trial every 2 weeks for three treatments)
- Treat the itch (steroids, antihistamines)
Diagnostic approach to pruritic cat: Step 3
- Food trial
- Atopica trial
- Lime sulfur dip trial
Step 4: if no response to food trial
Long term steroids?
Atopica?
Allergy desensitization therapy?
Lime sulfur trial to rule out demodex gatoi?
If response to Atopica?
- Continue long-term and reduce to every other day
- Monitor bloodwork every 6-12 months to ensure drug safety
- Consider allergy desensitization therapy (allergy shots?)
Anti-inflammatory doses of prednisolone in the dog?
- 0.5-1 mg/kg/day
Immunosuppressive doses of prednisolone in the dog
- 2 mg/kg/day
Dexamethasone doses
- I think you divide by 10
Short acting steroids for cats
- Prednisolone (goal is taper to every other day)
- Dexamethasone (taper to 2x a week)
Long acting steroids - use?
- Try to avoid
- Depomedrol every 3 months
- Triamcinolone acetonide give every 3 months
What do you need before starting steroids?
- Basic bloodwork
- FeLV/FIV
- Dermatophyte culture
- Auscult chest?
Serious side effects of glucorticoids?
- Skin fragility syndrome
- Medial curling of Pinnae (depomedrol)
- Congestive heart failure
- Diabetes mellitus
Do cats tend to get primary or secondary scaling?
- Secondary much more common
Is dry or greasy seborrhea more common in cats?
- Cats tend to get seborrhea sicca
What is most common cause of scaling?
- Secondary to miliary dermatitis
Dfdx for miliary dermatitis
- Flea allergy
- Others
- Dermatophytosis
- Cheyletiellosis
- Pyoderma
- Pemphigus foliaceus
other secondary causes of scaling
- Fleas
- Cheyletiellosis
- Demodicosis
- Pediculosis
Endocrine causes of scaling
- Hyperthyroidism
- Diabetes mellitus
What is feline acne?
- Focal primary follicular keratinization disorder
- Idiopathic
Clinical signs of feline acne
- Comedones
- Papules, pustules
- Crusting
- Nodules
Diagnosis of feline acne
- Derm database
- Scrape
- Cytology
- +/- culture and sensitivity
Treatment of feline acne
- Treat any complicating factors like bacteria (mupirocin and oral antibiotics)
- Symptomatic therapy for underlying keratinization disorder (Keratolytic/keratoplastic like benzoyl peroxide)
How common is plasma cell pododermatitis?
- NOt at all
- Rare
Clinical signs of plasma cell pododermatitis?
- Soft painless swelling of metacarpal/tarsal footpads
- White cross-hatches
- +/- ulcerate
Causes of plasma cell pododermatitis
- Unknown
- Maybe immune-mediated?
- ~50% are FIV positive
Treatment of plasma cell pododermatitis?
- Spontaneous regression
- Doxycycline
- Immunosupression
- Food trial
- Change in kitty litter?
- Surgery
Diagnosis of idiopathic seborrhea
- Cytology and biopsy
Treatment of seborrhea
- Difficult to manage
- SYmptomatic therapy
