Atopic Dermatitis Flashcards
other names for atopic dermatitis in dogs and cats
dogs: environmental allergies
cats: non-flea, non-food hypersensitivity dermatitis (NFNFHD), feline atopic syndrome (FAS)
atopic dermatitis
inflammatory and pruritic skin disease
what causes atopic dermatitis
genetic predisposition to produce IgE antibodies to environmental allergens
how are environmental allergens absorbed to cause atopic dermatitis
percutaneously
NOT inhaled or ingested
is atopic dermatitis curable
no - lifelong
can severely impact quality of life
pathogenesis of atopic dermatitis
allergens breach the skin barrier –> type I hypersensitivity reaction –> IgE mediated release of antibodies –> mast cell degranulation
also caused by immune dysregulation (initial Th2 cytokine production –> chronically shifts to Th1, 2, 17, 22 –> tissue damage and fibrosis)
how do allergens breach the skin barrier
dogs with atopic dermatitis have large gaps in the skin barrier –> allergens/pathogens are able to adhere and penetrate into skin layer
also have a loss of microbiome diversity –> increased adhesion of staph to skin
signalment for atopic dermatitis
typically 1 to 3 years old
can range from 6 months to 6 years
breeds: retreivers, GSDs, terriers, bully breeds, sharpeis, setters, poodles
can affect ANY breed
clinical signs of atopic dermatitis in DOGS
highly variable
often starts as seasonal and progresses to non seasonal
- severe pruritus
- erythema
- alopecia
- excoriations + salivary staining
- lichenification + hyperpigmentation
- secondary infections
distribution of atopic dermatitis lesions in dogs
face - muzzle, periocular
ears
legs
paws
glabrous areas (axilla, inguinal area)
often secondary otitis externa + conjunctivitis
clinical signs of atopic dermatitis in CATS
non-specific signs and reaction patterns
- marked facial pruritus
- facial lesions
- miliary dermatitis
- overgrooming
- bilaterally symmetric alopecia
- eosinophilic dermatoses
often get chronic recurrent otitis externa and superficial pyoderma
eosinophilic dermatoses
eosinophilic reaction pattern
lesion in response to hypersensitivity reactions (NOT a diagnosis - seen with FAD and food allergies)
- eosinophilic plaques
- eosinophilic granulomas
- indolent ulcers (lips)
how to diagnose atopic dermatitis
diagnosis of EXCLUSION
must first rule out:
- ectoparasites (fleas, FAD)
- bacterial and malassezia dermatitis
- dermatophytosis
- cutaneous adverse food reactions
can allergy testing be used to diagnose atopic dermatitis
NO - can only be used to support a previous diagnosis of atopic dermatitis
what are the types of allergy testing
serum and intradermal
when should allergy testing be performed
- AFTER a diagnosis of atopic dermatitis is made
- owner is interested in pursing allergen specific immunotherapy
- owner is committed to 1 year of specific immunotherapy following testing
- owner is aware that results will not be immediate
what are the treatment options for atopic dermatitis
- allergen specific immunotherapy
- medical therapy (corticosteroids, apoquel, cytopoint, cyclosporine, zenralia)
- supplements/diet change
allergen specific immunotherapy
allergen vaccines customized to a patient’s allergy testing results and known exposures in their environment
how is ASIT performed
regular inoculations of small quantities of allergen either SQ or sublingually
how does ASIT work
desensitizes the immune system by increasing Treg lymphocytes and IL-10 in response to the specific allergen affecting the patient
ASIT efficacy
moderate
can take up to 9-12 months to see results
ONLY treatment that can induce long term change in the immune response
what medical therapy is used for acute flare ups of AD
corticosteroids (prednisone)
what medical therapy is used for chronic management of AD
cyclosporine A
what medical therapy is used for acute flare ups AND chronic managemnet of AD
apoquel
cytopoint
corticosteroids
broad anti-inflammatory - does NOT target dermatitis specifically
short term remedy for acute flare ups in severely affected dogs
highly efficacious but has signficant side effects (PU, PD, PP, cutaneous changes, drug reactions)
apoquel (oclcitinib)
JAK inhibitor (JAK 1 and 3 pathways)
inhibits signaling cascade that releases pro-inflammatory and pruritogenic mediators (IL-31)
efficacy, adverse effects, contraindications, and uses of apoquel
75% efficacy, rapid onset of action (4-6 hours)
adverse effects: mainly GI
contraindicated in puppies <1 year, dogs with neoplasia, deep pyoderma, or demodicosis
uses: acute flare ups and long term management
- manages ITCH not inflammation
labelled for use in dogs, can be used off-label in cats
cytopoint (lokivetmab)
caninized monoclonal antibody that targets IL-31
reduces the quantity of circulating IL-31 and IL-31 receptors on nerve endings
efficacy, adverse effects, contraindications, and uses of cytopoint
efficacy: 75% in dogs within 1-5 days
adverse effects: none
uses: acute flare ups and chronic management
- manages ITCH not inflammation
DOGS ONLY
cyclosporine A (atopica, cyclavance)
calcineurin inhibitor
inhibits T cell synthesis of certain inflammatory and pruritogenic cytokines
efficacy, adverse effects, contraindications, and uses of cytopoint
efficacy: 80% of dogs and cats
adverse effects: common - vomiting, diarrhea, inappetance
contraindications: pets with liver disease
uses: long term management
- manages inflammation + itch
zenralia (iilunocitinib)
non-selective JAK inhibitor (JAK 1, 2, TYK2)
efficacy, adverse effects, contraindications, and uses of zenralia
efficacy: 50% itch reduction after 7 days
adverse effects: anemia, leukopenia, elevated liver enzymes, GI upset, fatal vaccine induced disease
- MUST discontinue 1-3 months prior to receiving vaccinations and not give for 28 days after a vaccination
DOGS ONLY
