Term
What are secondary lesions of Pruritic Dermatoses with ABSENCE of Primary Lesions
due to? |
|
Definition
| Secondary lesions are due to excoriations |
|
|
Term
| What are the 9 specific diseases of Pruritic Dermatoses with ABSENCE of Primary Lesions |
|
Definition
1. Atopy (atopic dermatitis) in Cats, Dogs, and Horses
2. Adverse Reaction to Food (ARF or Food Allergy
Dermatitis): Dogs and Cats
3. Eosinophilic Granuloma Complex (EGC) in Cats
4. Feline Demodicosis
5. Low Env't Humidity (skipped in lecture)
6. Poor Nutrition (skipped in lecture)
7. Feline PSychogenic Alopecia
8. Acral Lick Dermatitis in Dogs
9. Many Pruritic diseases classified under primary
lesions do not always present with Primary
lesions:
FAD and Culicoides hypersensitivity
Sarcoptes
Cheyletiella
Malassezia dermatitis
Notoedres Mange
Cutaneous ("epitheliotropic") Tcell Lymphoma |
|
|
Term
| what causes Atopy (actopic dermititis) in Dogs, Cats, and Horses? |
|
Definition
| a genetic predisposition to form IgE antibodies to innocuous env't substances with leads to prutitus. |
|
|
Term
| Is atopy a common or rare dz? |
|
Definition
|
|
Term
| What is the pathophysiology of Atopy? |
|
Definition
Type I hypersensitivity rxn
(percutaneously absorbed proteins (mold, pollens)->production of IgE by sensitized B cells-> IgE binds to dermal MC Fc Rc->next time MC encounters allergen-> allergen binds Fab portion of IgE and causes cross linking of the IgE molecules->MC membrane disruption-> stimulates MC to release stored mediators and immediately produce newly generated mediators |
|
|
Term
| what are the two things that the sensitized MC does upon second exposure to allergen in a Type I hypersensitivity rxn? |
|
Definition
1. Release stored mediators (histamine, serotonin,
acid proteases)
2. Immediate production of newly generated
mediators (PGs, LT, platelet activating factors) |
|
|
Term
| What are 3 common allergens in atopy? |
|
Definition
| house dust mites, pollen from plants whose pollen is wind-borne, and molds |
|
|
Term
| What is the age of onset for atopy? |
|
Definition
young dogs (~1-2 yrs)
horses usually <4 yrs
cats young to middle age |
|
|
Term
| what dog breeds are predisposed to atopy? |
|
Definition
| any terrier breed, Dalmations, Setters, LAbs, Goldens, GSDs, Boxers, English Bulldogs, Beagles, Miniature Schnauzers, Shar Peis |
|
|
Term
| what is the hallmark clinical sign for atopy? |
|
Definition
| Seasonal prutitus.....but may be perennial by middle age |
|
|
Term
| what are the primary lesions in atopy? |
|
Definition
|
|
Term
| what are the secondary lesions in atopy caused from? |
|
Definition
| caused from pruritus and resultant excoriations |
|
|
Term
| what is the most common cause of otitis externa |
|
Definition
|
|
Term
| what are some mild clinical signs of atopy consistent with? |
|
Definition
| allergic rhinitis and/or conjuctivitis |
|
|
Term
| what is the most common cause of recurrent pyoderma in dogs? |
|
Definition
|
|
Term
| what is the most common cause of Malassezia dermatitis in dogs? |
|
Definition
|
|
Term
| what is the distribution of atopy lesions in dogs? |
|
Definition
| often feet, face, ears, and ventrum, but can generalize |
|
|
Term
| what are the lesions and is the distribution of atopy lesions in cats? |
|
Definition
generalized pruritus and crusted papules (as with FAD, often referred to as milliary dermatitis)
May also have non-inflammatory alopecia |
|
|
Term
what is the distribution of atopy lesions in horses?
what other cs may they have |
|
Definition
face, ears, ventrum, legs
also have chronic pruritic utricaria |
|
|
Term
| what are some DDx for atopy? |
|
Definition
| all pruritic diseases, especially pruritic ectoparasites and food allergy |
|
|
Term
|
Definition
| History, Clinical Signs, Exclusion of other differentials! |
|
|
Term
| is specific allergy testing necessary to make a definitive dx of atopy? |
|
Definition
No!
allergy testing is used to select allergens for hyposensitization therapy |
|
|
Term
| what 3 things are included in tx of atopy? |
|
Definition
1. Must ALWAYS identify and treat all secondary infections (see superficial pyoderma Topic 6, Malassezia dermatitis Topic 9) while starting definitive treatments for atopy.
2. This is not a curable disease. Must rationally balance clinical signs with potential and real side effects of treatment.
3. There are 3 levels of therapy for atopy; often use an integrated approach. Treatments for a specific patient may vary over time due to intermittent secondary infections, drug side effects, development of concurrent skin diseases (food allergy, Scabies, fleas/ flea allergy, etc.) |
|
|
Term
| what are indications for level one innocuous, symptomatic therapy for atopy? |
|
Definition
1. for mild cases of atopy
2. as an adjunct to other therapies |
|
|
Term
| what 3 options are available for level one atopy therapy? |
|
Definition
1. Antihistimines
2. Essential Fatty acids: combination of omega 3 and omega 6 EFAs
3. Topical anti-pruritics |
|
|
Term
| what antihistamine should be used in level one atopy therapy in a cat? |
|
Definition
|
|
Term
| what antihistamines can be used in level one atopy therapy in a horse |
|
Definition
| hydroxyzine, chlorpheniramine, diphenhydramine, doxepin |
|
|
Term
| why are EFAs helpful in atopy level 1 therapy? |
|
Definition
| they are synergistic with antihistamines |
|
|
Term
| what are some topical anti-pruritics available for level one therapy for atopy? |
|
Definition
1. weak steroids (hydrocortisone)
2. antihistamine (diphenhydramine) or local
anesthetic (pramoxine) containing shampoos,
ointments, etc.
3. Oatmeal containing products (decreases pruritus
directly by complexing with proteins (allergens)
from skin and hair and preventing absorption by
the skin |
|
|
Term
| what side effects can any topical steroid cause? |
|
Definition
| localized, dermal/epidermal side effects |
|
|
Term
| what side effects can a potent topical steroid (teiamcinolone, betamethasone) caused if used extensively or on eroded skin? |
|
Definition
| systemic side effects can occur |
|
|
Term
| what is level 2a atopy therapy? |
|
Definition
|
|
Term
| what are indications for level 2a therapy in atopy? |
|
Definition
1. the only treatment that works quickly, therefore in
some cause is indicated for humane reasons
2. for patients with short allergy seasons (i.e.<3-4
mo) and for which there are no specific
contraindications for systemic steroid use |
|
|
Term
| what is the most common cause of main and tail alopecia in horses? |
|
Definition
|
|
Term
| what is the most common skin disease in horses? |
|
Definition
|
|
Term
| What systemic steroids do you use and how do you use them for atopy therapy? |
|
Definition
Oral short acting steroids only!!!!!
-begin at an anti-inflammatory dose and quickly taper to every other day at least possible dose. |
|
|
Term
| what systemic steroids do you use for atopy therapy in dogs, cats, and horses? |
|
Definition
dogs-prednisone
cats-prednisolone
horses-prednisolone
FOR ALL-Begin to taper within 3-7 days |
|
|
Term
| what are some direst dermatological side effects of systemic steroid therapy for atopy? |
|
Definition
| bilateral symmetrical truncal or facial alopecia and rat tail, poor regrowth of hair after clopping, coat color change, PROMINENCE OF CUTANEOUS VESSELS AND CAPILLARY FRAGILITY (bruise easily), COMEDONES< THINNING OF THE SKIN (esp abdomen), SEBORRHEA WITH EITHER A DRY OR GREASY HAIR COAT AND SKIN SURFACE, poor wonud healing, calcinosis cutis |
|
|
Term
| What are indirect effects of Glucocorticoids on the skin due to their immunosuppressive effects? |
|
Definition
Superficial pyoderma, Malassezia Dermatitis, demodicosis, dermatophytosis
(recurrent pyoderma and malassezia dermatitis are common and may cause mild to moderate pruritus) |
|
|
Term
| What are systemic SE of systemic steroids in atopy therapy? |
|
Definition
| PU/PD, polyphagia, weight gain, muscle weakness, increased incidence of DM, etc. |
|
|
Term
| when are systemic GCs contraindicated? |
|
Definition
| DM, recurrent pancreatitis, gastric ulcers, concurrent use w/NSAIDS |
|
|
Term
| What are the indications for Cyclosporine Therapy for Atopy? |
|
Definition
1. Patients for which steroids are contraindicated
(DM, recurrent pancreatitis)
2. As the sole of adjunct therapy for patients with
mild to moderate atopy and short allergy season
3. Does NOT interfere with IDST: can use during
steroid withholding period prior to IDST
4. AS AN ALTERNATIVE TO STEROIDS FOR PATIENTS
WITH SEVERE ATOPY THAT DO NOT RESPOND
ADEQUATELY TO HYPOSENSITIZATION THERAPY |
|
|
Term
| what are advantages of cyclosporine therapy vs systemic steroid therapy for atopy? |
|
Definition
| cyclosporine therapy has relatively fewer side effects |
|
|
Term
| what are disadvantages of cyclosporine therapy vs systemic steroid therapy for atopy? |
|
Definition
1. Cost (~$180/mo for a 20kg dog)
2. Takes several weeks of therapy to become
effective (so often need to use steroids during
first few weeks of tx)
3. Not effective in all patients
4. some owners have difficulty ADMINISTERING the
gel caps w/o food and giving in the correct time
frame
5. Only approced for use in dogs (but shows
equivalent efficacy in cats) |
|
|
Term
| What are the indications for level 3 atopy therapy (hyposensitization therapy based on identification of relevant allergens)? |
|
Definition
1. patients who dont get enough relief from level 1
tx
2. patients who would otherwise require systemic
steroids for > 3-4 mo/yr
3. Patients for which systemic steroids are contraindicated
4. Owner aversion to systemic steroids
5. Even when effective, cyclosporine therapy may be
cost prohibitive
6. relative east of administration |
|
|
Term
| what is the rationale for level 3 atopy therapy? |
|
Definition
| to "hyposensitize" the patient by giving injections of proteins to which the patient if allergic. Acts to down-regularte allergen-specific IgE production |
|
|
Term
| what test is best for allergy testing? |
|
Definition
Best when based on intradermal skin testing;
blood tests are 2nd choice |
|
|
Term
| Intradermal allergy test (IDST), how do you do it? |
|
Definition
1. sedation with xylazine (doesnt react w/drugs)
2. individual intradermal injections of small amts of
regional relevant allergens
3. Histamine as positive control; diluent as neg
4. Subject grading on a 0 to 4 scale as compared to
controls |
|
|
Term
|
Definition
1. measures skin reactivity which mimics
pathophysiological process resulting in ~75% of
patients responding to therapy
2. Can tailor a panel to your specific region |
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