Pruritus 1 - FAD and Atopy Flashcards
The unpleasant sensation of the skin the provokes the urge to scratch?
Pruritus
What does the owner see that indicates pruritus?
Biting Licking Chewing Scratching Gnawing Rubbing
What lesions do we see with pruritis?
Alopecia
Erythema
Excoriation
Followed by..
lichenification
Hyperpigmentation
Seborrhea
What are causes of pruritus in the dogs?
Allergens
Ectoparasites
Infections
What are possible allergens in a dog?
Flea bite allergy
Atopic dermatitis
Cutaneous adverse food rxn
Insect bite hypersensitivity/contact dermatitis
Vaccine/drug/heat and cold/sunlight/stress
Ectoparasites of dog?
Sarcoptes Demodecosis Cheyletiella Lice Chiggers
Infections causing pruritus in dog?
Pyoderma
Dermatophytosis
Yeast
What is most commonly assorted with pruritus of the caudal dorsum ?
Flea allergy
What is most commonly associated with pruritus of the of the feet (licking/chewing)?
Food allergy/ atopy
What is most commonly associated with pruritus of the elbows and ears?
Sarcoptic mange
What pruritic conditions are affected by seasonality?
Flea allergy
Atopy
Insect allergy
Which pruritic conditions are not affected by seasonality?
Scabies Food allergy Flea allergy Atopy Secondary infection Demodecosis
Pruritus can be graded on a scale of 1-10.. which conditions tend to be extremely pruritic at the high end of this scale?
Scabies
Flea bite allergy
Food allergy
If pruritis came before the lesions appeared.. what diseases will be at the top of you DDX?
Allergies
Scabies
If lesions showed up before pruritis.. what diseases will be at the top of your DDX?
Demodecosis
Dermatophytosis
What is generally part of your therapeutic plan in a pruritus case>
Flea control
Treat pyoderma if present - topical and systemic
Treat yeast infection if present
Treat for sarcoptes if suspected
Treat ear dz if present
Flea allergy dermatitis causes a type _____ hypersensitivity reaction
1
Classical distribution of flea allergy dermatitis?
Lumbo-sacral distribution
Lesions associated wtih flea allergy dermatitis?
Pruritic, crusting eruption and secondary erythema, seborrhea, alopecia
Excoriation
Pyoderma
Hyper pigmentation
Lichenification
Cats can present with a _____ dermatitis with flea allergy dermatitis
Miliary
T/F: an infestation of fleas is NOT necessary to cause flea allergy dermatitis?
True
Can only take one flea bite to set off allergic resposne
Diagnosis of FAD?
Age - any
Distribution of lesions
- dorsal lumbrosacral
- tail base
- cauda medial thigh
- ventral abdomen
- flank
Observe fleas or flea dirt
What is a definitive diagnostic test for FAD?
Flea antigen test 3 injections - negative control - saline - positive control - histamine - flea allergen
OR
Elevated serum allergen specific IgE
T/F: 80% of skin allergies are flea related
True
What is the treatment for FAD?
Flea eradication
- knock down product (nitenpyram, fipronil, imidacloprid, permethrin)
- insect growth regulator (S-methoprene, imidacloprid)
Environmental control
Monthly controls
What are monthly spot-ones that can be used for fleas in dogs>??
Advantage multi (imidacloprid and moxidectin)
Revolution (selamectin)
Frontline plus (fipronil and s-methoprene)
Vectra 3D (dinotefuran, permethrin, and pyriproxygen)
Promeris (metaflumizone and amitraz)
T/F: most of the flea eggs, larvae, an pupae live in the environment and not not the pet
True
—> environmental control is very important
You have a secondary bacterial infection from FAD.. how will you treat this?
Treat the secondary bacterial infection - topical antibiotics
Use prednisolone in moderate to severe cases once pyoderma is eliminated (lowest possible dose to control clinical signs—> reduce/stop pruritus )
What type of hypersensitivity reaction is atopy?
Type 1
Characteristic signs of atopy?
Pruritis
Chronic/relapsing/seasonal
Onset at 4months to 7yrs
Paws, face, distal extremities, elbow, ventrum, otitis externa
What is the most common cause of primary otitis ?
Atopy (allergic dermatitis)
What diagnostics can you do to confirm atopy?
Serum tests (RAST and ELISA tests) Intradermal skin tests
Detect —> allergen-specific IgE
When should allergy tests be done?
If clinical diagnosis of atopy is made
If allergen-specific immunotherapy (ASIT) is been considered
If allergen avoidance measures are been considered
What is the gold standard test for atopy?
Intradermal allergy testing
What allergens are tested for with intradermal allergy testing?
Seasonal —> trees, grasses, weeds, molds
Non-seasonal —> dust mites, cockamouse, moths, dander, storage mites
How will you preform intradermal allergy testing?
Avoid antihistamines and essential fatty acids 2 weeks before
Avoid oral and topical steroids for at least a month
No baths for at least 5 days
Clip hair and sedate
Marker to indicate where allergen is given
0.05ml of allergen
Pos control - histamine
Neg control- saline
Grade 1-4
What is hyposensitisation?
Injection of diluted allergens into the patient —> concentration increased up to a maintenance dose
What factors effect the efficacy of hyposensitisation in atopic dermatitis?
Patients selection - dogs with less than 10 allergens have a better response
Allergen selection - based on IgE testing
Dose of allergen - higher dose protocol appears better
Administration of immunotherapy - conventional vs rush protocol
Time —> 2-5months improvement
Duration of allergen specific immunotherapy
What are three possible therapies for atopy?
ASIT (allergen-specific immunotherapy) - hyposensitisation
Allergen avoidance
Symptomatic relief
What are two forms of allergy shots for allergen-specific immunotherapy?
Subcutaneous immunotherapy — increased the dose and concentration slowly
Sublingual immunotherapy - twice daily
What symptomatic therapy has the best evidence for atopy treatment?
Glucocorticoids Cyclosporine A Oclacitinib Monoclonal antibody IL31 Recombinant canine interferon gamma
What is the MOA of skin lipid therapy?
With atopy the epidermal barrier is compromised —> more penetration by allergens, irritants, and yeast
Skin lipid restores the barrier
—> dermoscent
—> duoxo
—> allerderm
In an allergic crisis of as a therapeutic trial for atopy, corticosteroids can be used.. what preparations can be used?
Oral prednisolone
Injectable dexamethasone
What are disadvantages to corticosteroids?
PU/PD
PP and weight gain
Iatrogenic hyperadrenocortisim Iatrogenic hypoadrenocorticism (if withdrawn quickly)
Less effective over time
More susceptible to infections
Urinary incontinence
Temperament/behavior changes
What is the MOA of cyclosporine A (Atopica)?
Anti-allergic and immunosuppressive by blocking Tcell activation
Better absorbed on empty stomach
Side effects of cyclosporine A (atopica)?
Vomiting/diarrhea
Exacerbate skin infections
What is the MOA of oclacitinib (Apoquel)?
JAK 1 and 3 inhibitor -> inhibits proinflammatory mediators and cytokines
Decrease itching and inflammation
What is a monoclonal antibody against IL31?
Cytopoint
— single injection 4-8weeks
IL31 is responsible for itching sensation
T/F: antihistamines are effective in treatment of atopic dermatitis?
False
What is the purpose of fatty acid supplementation in atopic dermatitis?
Steroid sparing effect
Improve cell membrane barrier
Less inflammatory eicosanoids
Less pro-inflammatory products
Less inflammation
