Feline dermatology (Proceedings)

There is more to know than Depomedrol!!!

Feline Integument

1. Unique Skin-Thinnest skin of all domestic animals.

2. Primary and secondary hairs ratio (1:10-24).

3. pH-5.6-7.4.

Eosinophilic Granuloma Complex

Group of inflammatory lesions affecting skin, mucocutaneous junctions and oral cavity of cats, usually due to genetic, parasitic, allergic, foreign body, viral and/or bacterial causes.

     It is a syndrome, not a diagnosis.

     Three variants of eosinophilic granuloma complex:

          1. Indolent ulcer

          2. Eosinophilic plaque

          3. Eosinophilic granuloma

     Indolent Ulcer

     Ulcerated lesion of upper lip.

     Alopecia, raised border.

     Blood and tissue eosinophilia is rare.

     Eosinophilc Plaque

     Moist alopecic papules and plaques.

     Usually abdomen but maybe on neck.

     Severe pruritus is usally associated.

     Blood and tissue eosinophilia.

     Eosinophilic Granuloma

     Pink to yellow raised plaque which maybe linear.

     Usually on caudal thigh of young cats.

     Nonpruritic.

     Younger and female cats predisposed.

     Focal collagen degeneration.

     Chin edema

EGC Pathogensesis

Genetic.

Allergic.

This is most common underlying cause.

Atopy, food allergy, mosquitoes.

Parasitic.

Bacterial.

Foreign body.

     Diagnosis

Clinical signs

     Histopathology

     Cytology

     EGC Treatment

     Depomedrol: every 2- weeks for 3 treatments.

     Antibiotics, especially Ditrim 120mg or Clavamox.

     Alpha-interferon 30-60 U PO/day, 7 days on, 7 days off.

     Intradermal allergy test- Allergy vaccine therapy.

     Oral Prednisone tapered to every other day.

     CO2 laser surgery.

     Antihistamines? Usually ineffective

     Cyclosporine therapy- 5mg/kg every day for 4-6 weeks, then every other day.

     Gold salt therapies.

Feline Acne

Alopecia, comedones, and follicular casts and crusts.

Rule out allergies, contact irritant reactions.

     Pathogenesis

Folliculitis.

Demodex, Dermatophytes, Malassezia, Staphylococcus

Keratinization defect.

Allergies.

Atopy, food intolerance, contact

     Diagnosis

Thorough history- include type of food/water bowls (avoid plastic

Cytology

Skin scrapings

Dermatopathology

     Acne Treatment

Cleansing

Antibiotics

Lymdyp?

Miconazole shampoos

Corticosteroids

Atopy

Seasonal to nonseasonal pruritus associated with elevated IgE.

Clinical signs include miliary dermatitis, alopecia, otitis externa, facial and cervical pruritus.

No age or breed predisposition.

Often misdiagnosed as Psychogenic alopecia??

     Diagnosis

Thorough history.

Skin scrapings.

Intradermal allergy tests:often difficult to read in the cat

Serologic allergy testing??-unreliable

     Treatment

Immunotherapy:75-80 have good to excellent response.

Antihistamines.

Chlorpheniramine 2-4 mg/bid

Claritin ?

Fatty acids.

GCC

Depomedrol?

Prednisone.

Adverse Reactions to Food

     Nonseasonal pruritus

Usually beef, lamb, fish, milk.

Nonimmunologic based intolerance related to elevated histamines in certain fish.

Steroid responsive??

No age sex or breed predilection.

     Clinical Signs

Clinical signs include miliary dermatitis, alopecia, otitis externa, facial and cervical pruritus may be prominent.

     Diagnosis

Dietary trials for 8-10 weeks with Eukanuba LB, Z/D, IVD diets, Home cooked often difficult.

Serology testing and Intradermal allergy testing are not reliable.

Demodicosis

Excessive proliferation of 2 species of demodex, D. cati and D. gatoi.

FeLV, FIV, DM may predispose to D. cati.

Variable pruritus but usually much more pronounced with D. gatoi.

     Diagnosis

Diagnosis with skin scrapings.

     Treatment

Lymdyps every 5 days for D. cati, and D. gatoi.

Pemphigus Foliaceus

Most common AISD

Pemphigus is Greek for "blister"

Acanthloysis:Keratinocytes lose their cellular attachments

Intraepidermal clefts are formed.

Neutrophils invade vesicle leading to pustule formation

     Clinical Signs

Facial crusts, ulcers

Large intact pustules??

Footpad hyperkeratosis, ulcers

Fevers, Anorexia

     Laboratory Signs

Leukocytosis with neutrophilia and left shift

Nonregenerative anemia

Dermatopathology: Intraepidermal pustule with acantholysis

and neutrophils or eosinophils

Cytology:Tzanck Prep: Hypersegmented neutrophils, no intracellular bacteria, acantholytic cells

     Treatment

Corticosteroids 2-4 mg/kg

Imuran Do not use in cats

Leukeran 0.1-0.2 mg/kg

Aurothioglucose 1mg/kg weekly for 12 weeks(difficult to obtain)

Paraneoplastic Alopecia

Rare syndrome, seen in older cats

Pancreatic carcinoma

Weight loss, anorexia

"Shiny skin" is seen

Exfoliative alopecia

     Diagnosis

Dermatopathology is suggestive to diagnostic

     Treatment

Grave prognosis

Supportive therapies