Canine Dermatologic Diseases

CANINE DERMATOLOGIC DISEASES

Introduction

  • Presented by Kara Schmidt, DVM

Atopic Dermatitis

Overview

  • Common hereditary skin disease associated with environmental allergens.

  • Typically affects dogs aged 6 months to 3 years.

Commonly Affected Areas

  • Face: mouth, eyes

  • Pinnae

  • Ventral abdomen

  • Feet

Clinical Signs

  • PRURITUS: Intense itching leading to discomfort.

  • Licking or biting at paws: Indicates discomfort and can exacerbate skin issues.

  • Scabbing or papules on skin: Visible manifestations of irritation and inflammation.

  • Recurrent ear infections: Commonly associated with skin allergies.

Diagnosis

  • History: Gathering information on dog's symptoms and environment.

  • Based on clinical signs: Identification of symptoms listed above.

  • Exclusion of other diseases: Must rule out conditions presenting similar symptoms.

Diseases to Exclude

  • Flea Allergy Dermatitis: Ensure flea prevention is in place.

  • Other Ectoparasites: Must be on comprehensive flea prevention covering mange, lice, etc.

    • Diagnosis: Requires skin scrapes.

  • Skin Infections: Evaluated through:

    • Skin cytology: Microscopic examination of skin samples.

    • Skin biopsy: Tissue sample for detailed analysis.

    • Response to antibiotics: Improvement on treatment can indicate infection.

Treatment Options

  • OTC Antihistamines: Over-the-counter allergy relief.

  • Immunotherapy: Customized treatment targeting specific allergens.

  • Steroids: Short-term relief for inflammation; not long-term due to side effects.

  • Anti-itch medication:

    • Apoquel: Fast-acting anti-itch medication.

    • Cytopoint: Injectable treatment for itching.

  • Antibiotics: Target secondary skin infections if present.

  • Prescription Diet: Consider veterinary diets to manage allergic reactions; example includes 1800PetMeds and Zoetis US.

Mast Cell Tumor (MCT)

Overview

  • Common tumor derived from rapidly dividing mast cells in connective tissue, which contain histamines and heparin.

  • One of the most common forms of skin cancer in dogs.

  • Breeds commonly affected: Bulldogs, French Bulldogs, Pugs, Pitbulls, and Boxers.

Clinical Signs

  • Incidental skin or subcutaneous mass: Often detected incidentally during examinations.

  • Highly variable appearance: Tumors may resemble lipomas, skin tags, or insect bites.

  • Intermittent changes: Tumors may shrink and enlarge over time.

  • Bleeding or bruising: Can occur when sampled or due to mass characteristics.

Diagnosis

  • Cytology: Characteristic blue/purple granules observed under the microscope.

    • Pre-sampling: Administer Benadryl to reduce tumor size beforehand.

  • Histopathology: Required for accurate tumor grading to determine severity.

Treatment

  • Surgery: Primary treatment to remove the tumor; ensure margins of 3 cm and 1 fascial plane deep for effective removal.

    • Pre-surgery: Administer Benadryl to minimize tumor size during procedure.

  • Chemotherapy: May be considered based on tumor grade.

  • Radiation therapy: Possible adjunct to surgery for high-risk cases.

Prognosis

  • Low grade MCT: Excellent prognosis with approximately 5% chance of recurrence or metastasis.

  • High grade MCT: Guarded prognosis with a higher chance of metastasis (spread).

Zinc Dermatosis

Overview

  • Uncommon, hereditary skin disease resulting from a zinc absorption defect.

  • Breeds commonly affected: Alaskan Malamute, Husky, Samoyed.

Clinical Signs

  • Pruritus: Itching often leading to secondary issues.

  • Erythema and alopecia: Inflammation and hair loss that progresses to scaling and crusting.

    • Affected areas: Around eyes, ears, bridge of the nose, lip margins, and foot pads.

Diagnosis

  • Skin biopsy: Definitive method for identification of the disease.

Treatment

  • Zinc supplementation: Core treatment to correct the absorption defect.

  • Anti-inflammatories: Optional for managing inflammation.

  • Antibiotics: Optional based on secondary infections.

Histiocytoma

Overview

  • Common, benign skin tumor of Langerhan cells that typically resolves spontaneously.

  • Most commonly affects dogs under 3 years of age.

  • Breeds affected: Boxers, Great Danes, Dachshunds.

Clinical Signs

  • Rapidly growing mass: Develops over 1-4 weeks and may progress to ulceration.

  • Appearance: Button-like, red growth often located on legs and face.

Diagnosis

  • Cytology: Examination of tumor cells.

  • Biopsy: Provides detailed information on tumor characteristics.

  • Histopathology: Confirmatory diagnosis for the nature of the tumor.

Treatment

  • Spontaneously resolves: Typically within 1-3 months without intervention.

  • Surgical removal: Considered if necessary for cosmetic reasons or complications.

Puppy Strangles/Juvenile Cellulitis

Overview

  • Rare, immune-mediated sterile granulomatous dermatitis affecting dogs less than 6 months of age.

  • Can impact many different breeds.

Clinical Signs

  • Acutely swollen face: Visible swelling in eyelids, lips, and muzzle.

  • Edematous ears: Swelling of ear tissues.

  • Possible concurrent lymphadenopathy: Especially submandibular lymph nodes.

  • Fever: Can occur alongside physical symptoms.

Diagnosis

  • Suspected from signalment, history, and physical examination (PE): Clinical assessment by a veterinarian is key.

Treatment

  • Steroids (immunosuppressive): Used to reduce inflammation and manage the immune response.

  • Antibiotics: Administered for secondary bacterial infections.

Prognosis

  • Good prognosis: Most dogs recover well, though there may be scarring.

Sebaceous Adenomas

Overview

  • Commonly observed benign growths of the sebaceous gland, often appearing as "warts."

  • Affects older dogs, especially smaller breeds such as terriers.

Clinical Signs

  • Raised, hairless, lobulated oily mass: Typically benign in appearance.

  • Presence: Can be single or multiple; usually small (less than 1 cm).

Diagnosis

  • Classic appearance: Often diagnosed based on visible characteristics.

  • Biopsy/Histopathology: Confirmatory testing if necessary.

Treatment

  • Cosmetic surgery: Recommended if growths increase in size, for aesthetic reasons.

Prognosis

  • Good prognosis: Generally benign and likely to develop more with age.

Lipoma

Overview

  • Common benign fatty mass that primarily affects older dogs.

Clinical Signs

  • Soft, freely movable, subcutaneous mass: Often described as rubbery in texture.

Diagnosis

  • Cytology: Identification of adipocytes (fat cells).

  • Biopsy/Histopathology: Necessary to confirm diagnosis and rule out malignancy.

Treatment

  • Cosmetic: Surgical removal recommended if the mass becomes problematic.

Prognosis

  • Good prognosis: Will likely continue to grow or develop new masses over time.

Wounds

Overview

  • Common injuries with various types of trauma.

Treatment

  • Surgical debridement: Removal of dying or necrotic tissue to achieve healthy, bleeding edges.

  • Laceration repair: May involve suturing or wound closure techniques.

    • Open wound management: May be needed for ongoing care and observation.

Contact Information

  • For further questions, contact:

    • Email: kara.schmidt@findlay.edu