Shawn Messonnier is a nationally known veterinarian, writer and speaker. He runs the Paws & Claws Animal Hospital in Plano, Texas, and is the author of the Pet Care Naturally series of books.
Text Copyright the American Kennel Club, Inc., 2005. No portion of this article may be reproduced without permission of the copyright holder. Reprinted with permission from AKC Family Dog, May/June 2005.
To subscribe: http://www.akc.org
Allergic skin disease, also called atopic dormant or simply atopy, is an extremely common skin disorder in dogs. In my practice, it is probably the most frequent skin problem we treat. Many of the affected dogs have not only atopic dermatitis but other problems that often occur in allergic dogs, including staphylococcal bacterial dermatitis or Malassezia yeast dermatitis.
Atopic dermatitis is often called inhalant allergic dermatitis, to signify the annual's reaction to foreign proteins (antigens or allergens) that are inhaled. In people, common indications of inhalant allergies include sneezing, runny eyes and nose, and wheezing. In dogs, while these symptoms are seen more often, the most common signs are manifested in the skin. Veterinarians now believe that dogs absorb a large amount of allergens through the skin, rather than inhaling them through the respiratory tract.
Diagnosing is easy when doctors look beneath the surface. Conventional treatments have often relied on corticosteroids and antihistamines, but alternative therapies include higher doses of antioxidant vitamins C, E, and A.
Although many breeds can develop allergic dermatitis, the condition is far more common in specific breeds, including many terriers, setters and retrievers, as well as Shar-Pei, Lhasa Apsos, Shih Tzu, Dalmatians, and Boxers. The most commonly affected group is terriers, with the West Highland White Terrier topping the list. In my own practice, retrievers are the most commonly affected, in large part because they are among the most popular dogs-and therefore have the greatest number.
Age of onset of clinical signs varies, but most dogs show signs of atopic dermatitis within 1 to 3 years of age, perhaps more correctly, one to three years of living in a place where they are exposed to allergens. Atopy results in dogs who are genetically predisposed to become sensitized to environmental antigens, mainly involving IgE immunoglobulin and to a lesser extent allergen-specific IgG antibodies.
Clinical signs most commonly seen in dogs include itching, which is often quite severe and is usually directed at the feet, abdomen, groin, armpits, and/or face. These dogs are often referred to as "armpit scratchers, face rubbers, and feet lickers." Some allergic dogs exhibit generalized itchiness all over the body. As a rule, the skin looks normal unless secondary infections are present. Some allergic dogs have chronic skin or ear infections as the only clinical sign. Doctors not familiar with this often mistakenly treat the skin or ears without searching for the underlying cause. As a result, the dog never really improves.
Diagnosis of the atopic pet is usually easy. The classic sign of itchiness without primary skin lesions points toward a diagnosis of atopy. Other possible diseases causing similar signs include food allergies,
although most of these dogs do have skin lesions, and occasionally sarcoptic mange. Atopic dermatitis should also be suspected with chronic skin infections, including ear infections.
The conventional treatments have relied on corticosteroids and antihistamines. Short-term treatment with the correct doses of both of these classes of drugs are effective and relatively safe. There are many long term side effects of corticosteroids, however, including increased thirst, urination and appetite, and susceptibility to infection, weight gain, Cushing's disease, Addison's disease osteoporosis, fatty-fiver disease, diabetes mellitus, gastrointestinal ulceration, cartilage degradation, and blood chemistry abnormalities. Side effects of antihistamines, including sedation and failure to control the itching, are less common.
Due to the potential for serious side effects, many veterinarians believe it is best to choose a therapy that is safer for long term use by these itchy pets. Complementary therapies are used to reduce or preferably eliminate the need for chronic drug therapy allowing resolution of the itching without the troubling side effects so often seen with conventional treatments. Following are several successful complementary therapies.
External decontamination with the appropriate shampoo, conditioner, or "leave-on" product is a simple but important part of therapy for atopic dogs.
A very important part of therapy for atopic pets is external decomitamnina tion using various shampoos, conditioners, and "leave-on'' residual products. The most benign include ingredients Such as aloe vera and colloidal oatmeal. More stubborn cases might require the addition of pantomime, antihistamines, or corticosteroids. Frequent use, often two to three times weekly, is essential to minimize antigen exposure, thus reducing the need for systemic medications. Any program that does not emphasize topical decontamination in the severely itchy clog is doomed to failure.
What once seemed bizarre, or complimentary is now accepted as part of the conventional approach to treating atopic disease by most doctors. Still, being a nutritional product, fatty acid therapy could fit under the banner of complementary treatment. We still do not know what is the best fatty acid, or even the best dose. I have been using omega-3 fatty acids at double to quadruple the label dose. Some experimentation with the various products might he needed. In addition, some of the newer diets with increased fatty acids might also be beneficial.
Higher doses of vitamins C, E, and A offer relief for some atopic dogs. These vitamins function to detoxify histamines, optimize adrenal function, decrease skin- cell destruction, and optimize function of the immune system.
Because antioxidants an alter blood levels of cortisol and thyroid hormones, a blood profile checking for adrenal and thyroid diseases is important prior to administration.
Some dogs respond to health-blend formulas, enzyme preparations, and barley-grass supplements. These products in some unknown way minimize the body's chemicals that cause itching and inflammation. nation. Enzymes allow increased nutrient absorption (especially plant enzyme preparations) these nutrients can then alter the chemicals responsible for the dogs itching.
Although hypoallergenic diets can help dogs with food allergies, they are not routinely prescribed for atopic animals. A trial close using one of these diets might lower the itching in dogs with both food allergy and atopy; diets with fatty acid supplements might also help atopic dogs. Finally, most doctors who work in complementary therapies would suggest a trial dose of homemade rather than processed food, or at least a "natural" processed food. These preservative free diets can reduce itching in some dogs. At some point in the treatment, before giving up and resigning the clog to a life of corticosteroids, try a homemade diet using fresh ingredients. Some pets respond dramatically to just this simple step.
Homeopathy involves the use of extremely diluted substances to heal the body through the release of vital energy. The rule in homeopathy is that ''like treats like,'' so a thorough history, examination, and laboratory testing are needed to properly choose the correct remedy. There are a number of remedies that can be tried in allergic dogs. Usually remedies of high potency are prescribed. The following remedies may prove helpful: sulphur, hepar sulph, arsen alb, and rhus tox.
By stimulating specific acupuncture points, doctors can help stimulate the dog's immune system and reduce the itching and inflammation associated with allergic dermatitis. The first case I ever treated with acupuncture was a dog with atopic dermatitis that had failed to respond to other complementary therapies. The dog, a Boxer, responded after three treatments and was maintained for over a year with treatments every three weeks before developing another problem which required additional treatments.
Both Chinese and Western herbal therapies can be useful in treating the atopic animal. It is important to try different herbs or combinations in order to match the correct therapy to the dog. I have had most experience with Chinese herbal formulas. Although I am usually able to treat dogs without herbs, some owners prefer herbal medicine, and some cases require a trial with herbs if they do not respond to other therapies. Several herbs that may be helpful include scutellaria, tribulus, anemnarrhena, and capillaris.
Because atopic dermatitis is a heritable condition, affected dogs should not be bred. Decreasing the gene pool for this condition will do a great deal in decreasing the number of allergic dogs produced in the future. Although there is no one best treatment for atopic dermatitis in dogs, there are a number of options. But remember: What works well for one dog may not have any effect on the next. Hopefully, by working with your doctor over time, you will find what works best for your dog. The goal of treatment is to reduce itching and to do so with a minimum of medication. Realistically, however, we will probably never completely eliminate this annoying condition.