Lecture 12 2/25/25 Flashcards
What can trigger canine atopic dermatitis?
-environment (50%)
-food (15%)
-environment + food (35%)
How do you begin the process of determining whether an animal’s AD is caused by food, environment, or both?
-if animal has patterns of disease that are strictly seasonal, then the AD is environmental and a food trial is not required
-food trial can reveal cause based on amount of improvement; full improvement indicates food trigger, partial improvement indicates mixed trigger
What is a novel protein/carb diet?
type of elimination diet in which the a patient is switched to a diet containing a protein/carb that the patient has never eaten before
What is a hydrolyzed diet?
type of elimination diet in which the proteins are processed into very small segments to prevent crosslinking by immune cells
How long should an elimination diet trial last?
-5 week trial in dogs and 6 week trial in cats will show a response in 80% of pets with food triggers
-8 week trial in dogs and cats will show a response in 90% of pets with food triggers
What is the provocation period of the elimination diet trial?
challenging the patient with the previous diet for 2 weeks to determine if the disease returns
What are the treatment options for canine AD?
-allergen-specific immunotherapy
-glucocorticoids
-cyclosporine/atopica
-oclacitinib/apoquel
-ilunocitinib/zenrelia
-lokivetmab/cytopoint
What are the characteristics of allergen-specific immunotherapy?
-desensitizes the immune system by exposing it to allergens
-establishes tolerance
-only therapy that can cure the disease; others simply mask it
What are the characteristics of glucocorticoid treatment of AD?
-inhibit arachidonic acid cascade
-increase anti-inflammatory cytokine transcription
-decrease inflammatory cytokine transcription
How does cyclosporine treat AD?
by inhibiting T cells
How do oclacitinib/apoquel and ilunocitinib/zenrelia treat AD?
by inhibiting JAKs
How does lokivetmab/cytopoint work?
specific neutralization of canine IL-31 (drug is anti-canine IL-31 antibody)
What are the components of feline atopic syndrome?
-feline atopic skin syndrome
-asthma/respiratory disease
-gastrointestinal disease
What is the pathomechanism of feline atopic skin syndrome?
hypersensitivity to food and environmental allergens
What is the clinical sign seen in all manifestations of feline atopic skin syndrome?
chronic pruritus that may appear as overgrooming
What are the four clinical phenotypes of feline atopic skin syndrome?
-miliary dermatitis
-self-induced alopecia
-head and face pruritus
-eosinophilic granuloma complex
What are the three presentations of eosinophilic granuloma complex?
-eosinophilic plaque
-indolent ulcer
-eosinophilic granuloma
How is feline atopic skin syndrome diagnosed?
-clinical diagnosis
-exclusion of other causes of pruritus
-cytology for EGC that shows eosinophils
What is the treatment for feline atopic skin syndrome?
-novel protein/carbohydrate diet or hydrolyzed diet
-allergen-specific immunotherapy
-glucocorticoids
-cyclosporine/atopica
What is the pathomechanism of allergic contact dermatitis?
-type 4 hypersensitivity
-delayed reaction to haptens derived from plants, topical meds, chlorine, etc.
-sensitization stage elicits dermatitis
How does the pathomechanism of irritant contact dermatitis differ from allergic contact dermatitis?
non-immune-mediated reaction
-no sensitization stage
-dermatitis occurs with first single exposure
What is the clinical presentation of allergic contact dermatitis?
-pruritus
-erythematous papular eruption in hairless/sparsely haired areas
How is allergic contact dermatitis diagnosed?
-history
-clinical signs
-patch test with suspected allergens
How is allergic contact dermatitis treated?
-avoidance of allergens
-glucocorticoids
-cyclosporine
What is the pathomechanism of canine eosinophilic folliculitis/furunculosis?
eosinophilic allergic reaction thought to be triggered by arthropod or insect bites
What is the clinical presentation of canine eosinophilic folliculitis/furunculosis?
-sudden onset
-papules, nodules, crust, and/or exudative lesions
-distribution on nasal bridge and muzzle
-painful
-dogs are otherwise healthy
-often occurs in dogs that are primarily outside
How is canine eosinophilic folliculitis/furunculosis diagnosed?
-typical clinical presentation
-eosinophils in cytology
-eosinophilic inflammation on histopath.
What is the treatment for canine eosinophilic folliculitis/furunculosis?
glucocorticoids; rapid response within 24 to 48 hours
What is the pathomechanism of feline mosquito hypersensitivity?
type 1 hypersensitivity to mosquito saliva
What is the clinical presentation of feline mosquito hypersensitivity?
-seasonal flares in the summer followed by spontaneous regression in winter
-pruritis
-papules/wheals/plaques on the nasal bridge, pinnae, and footpads
-seen in cats with outside access
How is feline mosquito hypersensitivity diagnosed?
-history, including seasonality and outdoor access
-eosinophils on cytology
-eosinophilic inflammation and flame figures on histopath.
-intradermal skin test against mosquito allergen
-Prausnitz-Kustner test
What is the treatment for feline mosquito hypersensitivity?
-avoidance of mosquito exposure
-symptomatic treatment with glucocorticoids
