The pruritic dog (Proceedings)

Pruritus

1. Unpleasant sensation that provokes desire to scratch.

2. Most common symptom in dermatology

3. Epicritic (sharp, specific) vs Protopathic (generalized) itch

4. Frustrations often makes this a multiple veterinarian disease!

Pruritic Dermatoses

Allergic dermatitis

Parasites

Infectious

Neoplasia

Hormonal diseases?

Drug eruption

Immune mediated

Must make accurate diagnosis for effective treatment

History and owner assessment is very important

Allergic Dermatitis

1. Flea Allergy - Used to be most common, is it still?

2. Atopy – Second most common?

3. Adverse Reaction to Foods

4. Contact Allergy – rare, does it occur in cats?

Food Allergy?

Adverse reaction to food maybe a better name

Not all food reactors are immunologic

Not all immunologic food reactors are IgE mediated

Clinical signs similar to atopics

Test diet length from 4-10 weeks

Eukanuba KO

Eukanuba FP

Hills Z/D, D/D novel protein, Purina H/A

Royal Canin diets

Home-cooked diets

20% of food reactors may only exhibit otitis externa

80% of food reactors have otitis externa

Serologic tests are worthless

IDAT

Gastroscopic Testing

EARS AND REARS?

Parasitic Dermatoses

Scabies

Demodicosis

Cheylitiella

Otodectes

Pediculosis

Helminths

Scabies

Intense pruritus in the dog

Lateral elbows, hocks, ventral thorax and ear margins are most common affected areas

Usually! poor response to GCC therapy, may actually cause mites to increase

Contagious to other pets and humans (especially if dog sleeps in bed with owner)

Physical examination

Skin scrapings of nonexcoriated papules usually best areas to find mites (ear margins and ventral thorax)

Always treat if suspect

Ivermectin, Selamectin (Revolution), Moxidectin (Advantage Multi),

Lime Sulfur dips

Infectious Dermatoses

Staphylococcus - Staph allergy/hypersensitivity is rare, often thought must show vasculitis on dermatopathology

Malassezia – Allergy to antigens or fermatation products. Desensitization Candidia

Dermatophytosis – Rare, usually T. mentagrophytes

Neoplasia

CTCL – Variable from none to extreme

Mast Cell Tumor

Hormonal Dermatoses

Hypothyroidism?

Cushing's Disease?

Calcinosis cutis – can often be very pruritic. Especially a problem if Iatrogenic.

Sertoli Cell Tumor – Rare, but some cases of hyperestrogenism are pruritic

Drug Eruption (variable pruritus)

TMS

Cephalosporins

Erythema multiforme

TEN – Most severe form, often fatal

What is Atopic Dermatitis?

Chronic, recurrent disease

Caused by hypersensitivity to environmental allergens

Mites, dust, pollens, molds, insects

Strong breed predisposition (Retrievers, Bulldogs, Terriers, Dalmatians, Shar Peis, Lhasas, Shih tzu,

Individual allergic threshold for each dog

Distribution of Pruritus and Skin Lesions in Atopy

     Diagnosis of Atopy

History

Physical Examination

Allergy Testing

IDAT vs In Vitro Allergy Testing

     Iintradermal Allergy Testing (IDAT)

The gold standard of allergy testing!

In vivo test

Tests for IgE, IgG4, and other mediated allergic responses

Highest percentage of responders to hyposensitization therapy.

Requires referral or increased training

Expense of maintaining allergens

Needs to be off antihistamines and steroids

     Atopy Treatment

Pharmacotherapy

Cyclosporine

Corticosteroids

Antihistamines

Antimicrobial therapy

Antibacterial, antifungal

Superficial or deep infections

Steroid Therapy

Use low potency oral meds

Use every other day therapy

0.1-0.2 mg/kg of prednisone/olone often effective

Temaril-P-Dosage??

Antimicrobial Therapy

Concurrent skin infections common with atopic dermatitis patients

Superficial and/or deep pyodermas (bacteria – Staphylococcus pseudintermedius or yeast – Malassezia pachydermatis)

Both pathogens can also act as allergens and exacerbate the atopic lesions

     Antibiotics

     Cephalosporins

     Clindamycin, Doxycycline

     Clavamox

     Antifungals

     Ketoconazole

     Itraconazole

     - Fluconazole

When do I use Atopica?

Atopics who fail to respond to immunotherapy or during induction of immunotherapy

Older animals especially diabetics who cannot tolerate GCC

When Do I Not Use Atopica?

Generalized Demodicosis

Scabies

Early atopics

Dogs with malignancy