Feline Pruritis Flashcards
how do we diagnose itchy cats?
- history
-cats manifest itching as overgrooming
-scratch grooming of head and neck (scratching with hind paws) (physiologic per day: 86 seconds)
-oral grooming of trunk and legs: stroking tongue through the pelage and nibbling with incisor teeth (physiologic per day: 1 hour) - presence of secondary lesions:
-excoriations (self-induced erosions or ulcers)
-self-induced alopecia
-lichenification
-hyperpigmentation - presence of broken hair tips on trichograms
- presence of hair in feces
what are the main differentials for feline pruritis?
- ectoparasites:
-notoedres
-otoectes
-demodex gatoi
-cheyletiella - infections:
-malassezia dermatitis
-dermatophytosis
-herpes dermatitis - hypersensitivity dermatitis/allergic skin
-fleas
-food allergens
-environmental allergens (atopic skin syndrome) - psychogenic alopecia
describe felie pruritis due to ectoparasites
- suspect notoedres cati:
-dx: skin scrape, rarely histopathology
-tx: selamectin (revolution) every 2 weeks x3 or isoxazolines (fluraner for cats) - suspect otodectes cynotis:
-otic pruritis with secondary skin trauma
-dark coffee ground otic discharge is classic (but may also be malassezia)
-clinical diagnosis with supportive findings of mites
-tx: selamectin or isoxazolines as for notoedres cati - suspect demodex gatoi:
-surface mite, contagious
-pruritis and self induced lesions, multiple cats in household affected
-dx: superficial skin scrape (short bodied mite) but tricky to find so scrape multiple areas! if don’t find does NOT rule out
-tx: isoxazolines
describe feline pruritis due to infections
- feline herpes/ulcerative dermatitis: due to stress
-eye lesions, then skin or skin at same time as eye - malassezia dermatitis/sebhorrheic dermatitis: very rare in cats!
-except sphinx bc oily - dermatophytosis
describe feline hypersensitivity dermatitis diagnosis (feline HD)
- rule out other causes of itchy cat:
-ectoparasites beyond fleas: history/localization/skin scrape
-infections: skin cytology
-dermatophytes: DTM, PCR - presence of 4 clinical reaction patterns:
-miliary dermatitis
-self-induced alopecia (most common)
-head and neck pruritis/erosions
-eosinophilic dermatitis (indolent ulcers, eosinophilic plaque, eosinophilic granuloma)
-patterns develop with any allergic causality though!
what all can cause feline HD?
- fleas
- foods
- mites, pollens, molds
so now we can also call it atopic skin syndrome
describe therapeutic approach to feline HD
- ID and address flare factors
- symptomatic treatment of itch and/or inflammation
- prevention of HD flares
describe therapeutic approach to a cat with feline HD due to fleas
- environmental treatment of flea cycle
- flea treatment of all animals in house
- address itch and inflammation
describe therapeutic approach to a cat with feline HD due to food allergens
- only in cats with non-seasonal signs of feline HD with fleas ruled out!
- elimination diets with novel proteins:
-RC rabbit/green pea; ultamino diet - duration: usually 8-12 weeks
-eliminate itch and inflammation with medications as during elimination trials in dogs with atopic dermatitis - diet trial:
-phase 1: use any meds to resolve all secondary complications; initiate elimination diet (transition) with unflavored medication
-phase 2: taper meds and stop
-phase 3: provocation re-challenged with old diet for max 2 weeks
-phase 4: return to elimination diet
-phase 5: blinded provocation re-challenges for max 2 weeks
describe glucocorticoid drugs to target itch and inflammation for feline HD
*oral admin of tablet-type meds can be very challenging so when possible use liquid formulations!
- oral:
-prednisolone
-dexamethasone
-triamcinolone
*never prednisone due to low bioavailability/conversion - topical:
-triamcinolone spray - systemic injectable:
-methylprednisolone acetate (depo-medrol); not good guidelines on use
side effects of glucocorticoids: more common with longterm injectable (depo-medrol)
-systemic: CHF, DM, steroid hepatopathy
-dermatological: alopecia, thin skin and skin fragility
describe cyclosporine for feline HD
higher dose than in dogs; give until achieve clinical remission then taper
-AVOID COMPOUNDED!!! low bioavailability
-side effects:
–acute: GI upset (freeze, give with meal)
–chronicL increased severity of T. gondii infection in seronegative cats
-always combine with something that works faster (like pred)
describe oclacitinib for feline HD
no clinical side effects but limited info on safety in cats
-OFF LABEL usage only
describe H1R antihistamines for allergies and itch in cats
no evidence for efficacy in reactive phase
proactively has not been studied
maropitant for allergic inflammatio and itch in cats
substance P and neurokinin 1 receptor inhibitor
may decrease itch scores for non-flea non-food HD
-head and neck pruritis not respond as well so really plus or minus and also a pill so not super practical for cats
describe prevention of environment-induced HD flares
similar to cAD prevention in dogs
-AIT or symptomatic
compare and contrast subcutaneous and sublingual AIT
- subcutaneous:
-side effects: anaphylaxis (rare), mild GI upset, increase in AD symptoms - sublingual:
-side effects: oral pruritis/redness after dosing
both:
-main advantages: only true disease modifying intervention, long-lasting protection, prevents progression to severe
-disadvantages: limited efficacy, long time to efficacy, adverse effects and safety possible
how to select allergens in AIT for FASS?
- intradermal test: can be hard to see results in cats
-tissue bound IgE, long half life (weeks to months) - IgE serology
-serum/cicrulating IgE
-shorter half life
either way, most common allergens:
1. house dust mites
2. storage mites
3. pigweed, house fly, moth, cockroach
describe feline psychogenic alopecia
- only diagnosed if primary dermatologic and other medical conditions have been ruled out
-likely overdiagnosed - behavioral treatment recommended
