Small Ani. Med- Diagnostic Approach to the pruritic cat 2 (Lecture 5+6)

drraythe's version from 2016-04-29 14:39

Feline Atopic Dermatitis (allergic dermatitis) + Psychogenic alopecia (not allergic, cats are just crazy)

Question Answer
Feline atopic dermatitis--> what kinda hypersensitivity reaction?Type I hypersensitivity reaction
what is the barrier dysfunction like in Feline atopic dermatitis?Barrier dysfunction not characterized in cats
does feline atopic dermatitis have pruritus?yes!
5 main clinical signs of feline atopic dermatitis?(1) Pruritus (2) Self-induced alopecia (Focal (facial), generalized, bilaterally symmetrical, regional) (3) Papules, miliary dermatitis (4) Eosinophilic skin disease (5) Sneezing, asthma less common
how do you dx feline atopic dermatitis?Made by exclusion of everything else!
2 broad categories of ways to tx feline atopic dermatitis?(1) Allergen-specific immunotherapy (2) Pharmacologic management of pruritus
how do you go about Allergy testing in cats for atopic dermatitis? WHEN would you do this?Some dermatologists do NOT recommend doing IDAT (intradermal allergy testing) because cats do not make “nice” wheal-flare reactions, which leaves Serum allergy testing. Allergy testing is only recommended if owners want to follow through with hyposensitization with allergen-specific immunotherapy (ASIT)
allergen-specific immunotherapy (ASIT)--> what are the most common allergens for cats?House dust mites, house dust, weeds, grass, tree pollens
Do cats respond well to allergen-specific immunotherapy (ASIT)?outcome as good as dogs, perhaps even better
Pharmacological control of pruritus for feline atopic dermatitis... 3 types of drugs you can use?(1) corticosteroids: PredniSOlone for cats (~1mg/kg/day then taper) (2) Cyclosporine A (7mg/kg or 25mg/cat per day) (3) Antihistamines (Chlorpheniramine, Clemastine)
what are two types of antihistamines which seem to work better for cats than for dogs?Chlorpheniramine, Clemastine
what are possible Adverse reactions in using corticosteroids to treat feline atopic dermatitis?(she said in class tends to be tolerated better in cats) PU/PD/PP not as common in cats, Skin fragility, Curling of pinnae
what are possible Adverse reactions in using Cyclosporine A to treat feline atopic dermatitis?GI upset, possible renal toxicity, Hirsutism (excessive hair growth)
what are possible Adverse reactions in using antihistamines to treat feline atopic dermatitis?Pretty safe, Effectiveness questionable
holy cow, what happened here?? skin fragility due to corticosteroid use (or hyperadrenocorticism) to tx feline atopic dermatitis-- happened from scruffing the cat
Why is Mr. fluffybutt so EXTRA fluffy? Cats on Cyclosporin A to treat feline atopic dermatitis can develop hirsutism (excessive hair growth0
If pruritus is still not adequately controlled and self-induced alopecia is the main clinical problem, what might you consider the prob is?Consider psychogenic alopecia
what is psychogenic alopecia?Compulsive disorder of overgrooming with Alopecia, often bilaterally symmetrical, that has no underlying medical cause
how do you dx psychogenic alopecia?dx of exclusion
what type of cats are predisposed to Psychogenic alopecia?Fancy breeds (esp. Oriental breeds) predisposed (stressful environment also plays a key role)
clinical signs of psychogenic alopecia?Alopecia that is generalized or occasionally focal, Usually no associated secondary infections
4 things you can do for tx of psychogenic alopecia?(1) Removal from stressors (2) Environmental enrichment (3) Behaviour modification (4) Clomipramine or other antianxiolytic medications

Eosinophilic granuloma complex (ECG) / Eosinophilic dermatoses + summary

Question Answer
what are the three Eosinophilic dermatoses?(1) Eosinophilic granuloma (2) Eosinophilic plaque (3) Indolent (rodent) ulcer
eosinophilic dermatoses are basically what?A manifestation of feline hypersensitivity reaction. Considered a reaction pattern specific of the cat, not a disease
how do eosinophilic dermatoses appear histologically?Histologically inflammatory reaction with prominent eosinophils and eosinophil induced lesions (flame figures, “collagen degeneration”)
are eosinophilic dermatoses environmental or genetic?Can be genetic only, but usually develops in the face of allergic disease
graph explaining contributing factors to ECG
Eosinophilic granulomas---> how do these appear/look?Appear as nodules on the skin, linear plaques on the skin, or oral plaques (tongue, palate). Always a raised lesions
do eosinophilic granulomas cause pruritus?Variably pruritic (dependent on location)
what is the distribution of eosinophilic granulomas like?Found in oral cavity, lower lip, caudal thighs, footpad/interdigital space
what on earth is this?? This is oral eosinophilic granulomas
what is this? This is "fat lip" which is a manifestation of eosinophilic granuloma complex that is a focal swelling only localized to the middle of the bottom lip. Generally this kinda lesion doesnt bother the cat
Where do you see linear eosinophilic granulomas?linear is only on the caudal thighs
Eosinophilic plaques--> how are these formed/ what do they look like?Coalescing papules to plaques on the skin. Often eroded surface with yellow-tinged film. Lesion starts out as flat, then becomes raised!
do Eosinophilic plaques cause pruritus?Markedly pruritic
what is common distribution of eosinophilic plaques?Found in the inguinal/ventral abdominal regions, medial thigh
what are Indolent ulcers/ what do they look like?Unilateral or bilateral yellow-tinged ulcer
Do indolent ulcers cause pruritus?Non-pruritic
what is the distribution of indolent ulcers?Usually affects only upper lip (why you should always do oral exam in allergic cat) doesn't affect eating or drinking, non=painful
what does cytology of EGC problems look like?eosinophilic granules in cells
what does histopath of EGC problems look like?pink is eosinophils- almost all eosinophils
You do a histology of a EGC problem and you see this pink blob (circled on pic) what his going on? these are "flame figures" and it is basically big areas of eosinophilic materials
2 DDx for Eosinophilic granulomas?SCC, Plasma cell pododermatitis
DDx for Eosinophilic plaques (4)SCC, Mast cell tumor, epitheliotropic T-cell lymphoma, Cutaneous lymphocytosis
2 DDx for Indolent ulcer?SCC, viral infection (herpes, calicivirus, cowpox)
Summary--> diagnostic approach to the pruritic cat--> 7 steps to diagnostically approach the pruritic cat(1) Rule out ectoparasites (2) Implement strict flea preventative program (3) If skin lesions present, cytology / bx (4) Treat secondary infections if present (5) Begin elimination diet trial 8-12 weeks (6) Diagnosis of atopic dermatitis (7) Treat with systemic medication or allergy test + ASIT