Derm Allergies Flashcards
define summation effect
summary of all factors that can contribute to pruritus, both allergenic and non-allergenic
What are some examples of non allergenic factors causing summation effect
bacterial pyoderma, Malassezia (yeast) dermatitis, Seborrhea sicca (dry skin)
What 3 things contribute to summation effect?
Atopic dermatitis, flea allergy, bacterial pyoderma
What is the pruritic threshold?
the point where pruritic stimuli exceeds the threshold for a particular animal
when pruritic load becomes greater than the pruritic threshold=
Pruritus
Summation of all allergens that come together to exceed pruritic threshold=
allergen load
A patient that is allergic to grass, house dust, and human dander experiences clinical pruritus only in summer. What is this an example of?
Allergen load
Flea allergy dermatitis is type ___ and ___ hypersensitivity
1 and IV
type 1 is IgE mediated Hypersens. and type 4 is cell-mediated- delayed hypersens.
Type __ sens explains why flea allergy can be neg on IDAT or serology tests
type IV
up to 30% of flea allergy dermatitis dogs may only have delayed rxns
what is the allergic component of flea allergy dermatitis
flea saliva of Ctenocephalides felis
location of lesions from flea allergy dermatitis (usually occurs in patients less than 5 years old)
Dogs- caudal half of body- ribcage and on back (waist dz) **dorsal LS region, inverted triangle shape*
Cats- same but also around neck and military dermatitis
Pyotraumatic dermatitis aka ____, usually occurs on dogs’ dorsal _____. Usually occurs with what in dogs and cats?
Hotspots- usually on dogs’ dorsal hips, often occurs with atopic dermatitis in dogs and cats
flea allergy dermatitis- clinical signs in CATS
combo of reaction patterns, miliary dermatitis, eosinophilic granuloma complex, symmetrical alopecia (flanks and abd, usually self induced, skin is non inflammed)
signs of flea allergy dermatitis but no fleas seen, can it still be FAD?
No fleas seen does NOT rule out FAD, esp. in cats
Treatment of flea allergy dermatitis-
avoidance of allergen, immunotherapy is NOT beneficial, initiate flea control in all dogs/cats, can be challenging, stop the itching, treat any secondary infections
With any kind of allergy, you need to see if there’s any infections and tx those as well as the primary issue. T/F
True!!
Flea allergy dermatitis treatment in cats vs dogs
Cats: flea control/preventatives, oral prednisone/prednisolone
Dogs: apoquel, cytopoint, address hotspots
Canine atopic dermatitis
second most common allergy, genetically predisposed inflammatory and pruritic allergic skin disease with IgE
first most common is flea allergy
non seasonal itchy dogs-
see if food allergies are a components, usually beef allergy in dogs
can be combo of food AND environment
Canine atopic dermatitis is a multifactorial disease, results from interaction between ___ and ____, genetics play a role
host and environment
Canine atopic dermatitis involves with immunologic alterations?
Type 1 hypersens. TH2 lymphocytes (IgE, cytokine profile) Pruritogenic cytokines (IL-4, 5, 13, 31)
Allergens are processed in skin by ______, with ___ being the most important
APC’s; epicutaneous
Canine atopic dermatitis- age onset is __ months to ___ years
6 months to 7 years
Canine atopic dermatitis pruritis location
feet, face, ventrum, extremities, medial antebrachial region and fold of elbow
canine atopic dermatitis unique locations-
medial antebrachial region and fold of elbow
Otitis externa-
infectious or allergic, seasonal or non-seasonal
conjunctivits, rhinorrhea, urticaria, sneezing, pyotraumatic dermatitis (face, neck, trunk) are all CS that may be involved with what condition?
Atopic dermatitis
Canine atopic dermatitis- secondary skin infections include:***
bacterial folliculitis/pyoderma, pododermatitis, staphylococcus pseudointermedius
Malassezia dermatitis and pododermatitis Malassezia pachydermatis
What is the second most common dermatitis in dogs?
First is flea allergy!!!
Canine atopic dermatitis
feline atopic dermatitis- increased numbers of APC’s and ______ in lesions of skin along with increased _____ cells
T-lymphocytes; mast cells
Signalment of feline atopic dermatitis
Typically YOUNG cats, between 6 months and 2 yrs, pruritus is the most consistent CS, resulting in alopecia and some may have otitis externa
where is the most common locations of feline atopic dermatitis?
Face or head and neck
Allergen- Specific immunotherapy options in dogs and cats:
- Requires ID of allergens (skin testing/serology)
* Only therapy that targets immune system to alter response to allergens and outcome of disease
? is a non flea, non food hypersen.
Feline atopic dermatitis
Secondary infections of atopic dermatitis are more common in cats or dogs**
Dogs
It is okay to use cytopoint in cats if nothing else is available. T/F
False!!!
What is the 3rd most common hypersen in dogs and cats?
Food allergy
are serological tests reliable for food allergy diagnosis? What about saliva tests, hair pluck tests?
Nope; nope
What is the gold standard for diagnosis of food allergies?
Food elimination diet/trial with relief of CS and then fed again causes revamping of CS
How long should a food elimination diet be?
Positive response in 6 weeks, more than 90% of dogs and cats reach max improvement by 8 weeks
What diets should we use for food elimination trial?
Novel protein OR hydrolyzed diet (also use antipruritic meds as needed while starting food trials and hopefully can back off and even stop them)
Type 1, 3, 4 hypersens=
food allergy hypersensitivity
