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About Eric Barchas, D.V.M.

Eric Barchas, DVM is a veterinarian who lives and works in the San Francisco Bay Area. His emphasis is on small animal medicine, emergency medicine, hospice and wellness. An avid traveler, he has studied lions in Botswana and salmon in southern Chile.

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Allergies in Dogs

Animals Affected

Dogs

Overview

Allergies are the most common cause of skin problems in dogs.   In dogs, allergies often cause itching, hair loss, and inflammation of the skin.   In some dogs, allergies help trigger ear problems (such as ear infections) as well as skin problems.

Allergens are compounds, substances, insects, or parasites that cause allergies.   In dogs, the most problematic allergens are fleas, environmental components and household products (such as pollen, grasses, spores, detergents, and danders), and proteins in food.

Allergies cannot be cured, and they are a common cause of frustration for dog owners. However, a large number of management options are available for dogs with allergies. Most cases of allergy in dogs can be controlled, with symptoms reduced to levels that are tolerable for the dog and the people living with it.

Symptoms

Skin problems are the most common symptom of allergies in dogs.  Skin problems may occur anywhere on the body, but the most commonly affected areas are the base of the tail, the groin, the armpits, and the feet.

  • Itching is the most consistent symptom in dogs that suffer from allergies. Itching may cause dogs to scratch with their nails, or to lick their feet (or other parts of the body) excessively.
  • Hair may be thin or absent over areas of skin that are affected by allergies.
  • The skin in affected areas may be red, thickened, or malodorous.  Red bumps may develop in the affected areas.

In addition to skin problems, some dogs with allergies develop redness, itching, irritation, or infection in their ears.

Risk Factors

  • A genetic or hereditary predisposition to allergies appears to be the leading risk factor.
  • Dalmatians, Retrievers (especially Golden Retrievers), and Terriers are at increased risk.
  • Inadequate flea control triggers many cases of allergy in dogs.

Complications

Allergies cause discomfort that can lead to decreased quality of life.  Dogs with severe allergies may suffer from interruption of sleep due to itching.

Infection with bacteria or yeast may occur in skin or ears that is compromised by allergies. Allergies that affect the ears may lead to head shaking and aural hematomas.

People that care for dogs with allergies often become frustrated by the intractable nature of the problem.

Diagnosis

Most skin and ear allergies in dogs are diagnosed by visual inspection of the affected areas during a physical exam.  Diagnostic tests including cultures for bacteria and ringworm, tests for mange and other skin parasites, or biopsy may be performed.

Blood tests for allergies are used in some cases to determine which allergens are causing problems.  Skin allergy tests may provide results that are superior to blood allergy tests. However, skin tests are more involved and unpleasant for the patient.

Dietary trials with hypoallergenic diets are used to diagnose (and treat) food allergies.

Treatment

A variety of allergy treatments is available.  However, none of the treatments consistently cures allergies.

The simplest and safest forms of treatment involve reducing exposure to problematic allergens.

  • Appropriate flea control should be implemented in all pets that suffer from allergies.
  • Diets designed specifically for dogs with allergies are available from veterinarians. These foods, called hypoallergenic diets, dramatically reduce symptoms in dogs that are allergic to proteins in food.
  • Dogs that suffer from itching on their feet (manifested by excessive licking of the feet) may benefit if pollen and other allergens are washed from the feet each day. Cool water can be used to cleanse the feet after walks.
  • Problematic allergens identified by blood or skin allergy tests should be removed from the dog's environment if possible.

Several mild treatments for allergies are safe and effective in many cases.

  • Soothing baths with natural compounds such as colloidal oatmeal may relieve itching and discomfort from allergies.
  • Omega-3 oils (fish oils) may strengthen the skin's natural resistance to allergies. Specially designed combinations of omega-3 oils are available from veterinarians.
  • Soothing topical sprays may relieve symptoms of allergies that are limited to a small area of skin.

Antihistamines, including hydroxyzine (Atarax®), diphenhydramine (Benadryl®), and chlorpheniramine provide relief from symptoms of allergy in some dogs.  These medications generally are not as effective in dogs as they are in humans.

Dogs that have undergone blood or skin tests for allergens may benefit from allergy shots. This procedure is known as hyposensitization.

For dogs that suffer from severe, refractory allergies, potent medications are sometimes used to control syndromes.

  • Prednisone and related drugs are very commonly used to treat allergies.
  • Cyclosporine A (modified), also known as Atopica®, is beneficial in some cases of canine allergy.  Atopica is more expensive than prednisone, but has fewer side effects in most cases.
  • Genesis®, a topical formulation containing a medicine related to prednisone, reduces symptoms of allergy in many dogs.  Side effects occur less frequently with Genesis than with prednisone.

Follow-up

The effectiveness of allergy treatments is measured by a reduction in symptoms.

In most dogs, allergies are long-term, chronic problems.  However, some dogs outgrow allergies as they age.

In some dogs, allergies have a seasonal or cyclical nature.  These dogs may alternate between symptom-free periods and periods during which they require treatment.

Miscellaneous

Hay fever, in which the eyes and nose are affected by allergies, is not common in dogs.

Skin allergies in dogs are sometimes called atopy or atopic dermatitis.

Some dogs are allergic to human or feline dander.   This means that dogs can be allergic to people or cats.

Colloidal oatmeal, which is an ingredient in many allergy shampoos, is derived from oats.

Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.