Treating Atopy in Dogs

Dog Breeds

The goal for treating atopy in dogs is to eliminate or at least minimize exposure to the causative allergens and thereby eliminate the dog’s persistent discomfort.

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Introduction

Atopy is one of the most common allergic skin disorders in domestic dogs and is uniformly frustrating for owners and for their pets. It causes intense pruritis (itchiness), scratching and associated skin lesions, with secondary infections being common as well. Fortunately, with patience and persistence, most cases of canine atopy are treatable or at least manageable. The therapeutic goal for this disease is to eliminate or at least minimize exposure to the causative allergens and thereby eliminate the dog’s persistent discomfort.

Treatment Options

The appropriate treatment protocol will depend upon the underlying cause of the particular dog’s atopic condition. Key factors include seasonality of the symptoms, the distribution and severity of associated skin lesions, the presence of any secondary bacterial or yeast infections, client commitment and compliance and cost considerations. Most cases of atopic dermatitis can be treated on an outpatient basis. Owners should recognize that this is a progressive disorder that rarely goes into remission and cannot be cured in the ordinary sense of that word. Lifelong treatment or management usually is necessary to return the dog to an acceptable and comfortable quality of life. Unfortunately, most dogs have allergies to a number of different environmental factors, and it rarely is possible to identify and eliminate all of them from the dog’s normal living circumstances.

One of the first therapeutic steps should be to remove any known or identifiable sources of itchiness other than atopy. These may include flea infestation, ticks, mites, lice, infection, food allergies or other skin irritants. Acute-onset and mild cases of canine atopy usually can be managed with oral antihistamines and with omega-3 essential fatty acid nutritional supplements, usually derived from fish oils. Together, these are reported to alleviate pruritus in up to 30% to 40% of affected dogs. Antihistamines can cause drowsiness, lethargy, anorexia, vomiting, diarrhea and sometimes nervousness, so owners should watch for these possible side effects. If secondary bacterial skin infections occur, oral and topical antibiotics can be prescribed. Yeast or fungal infections typically can be treated topically or orally as well. Shampoos and other topical treatments also are available to help control skin infections and to soothe and rehydrate inflamed, irritated skin.

In especially severe or chronic cases of atopy, corticosteroid therapies can be used. Steroids are probably the most effective medication for controlling the itchiness associated with environmental allergies and for breaking the itch-scratch-itch cycle. However, long-term steroid use also carries the most serious potential adverse side effects; steroid treatment should be tapered to the very lowest dosage necessary to control the condition. Often, steroids are given temporarily or intermittently, to provide short-term relief until the symptoms of atopy have been brought under control. Cyclosporine, which is an immunosuppressant drug, has also proven effective in controlling pruritus associated with severe or chronic atopic dermatitis. This treatment is quite expensive, especially for large-breed dogs. The most common side effects of cyclosporine are vomiting and diarrhea. A combination of corticosteroids and antihistamines has been shown to control itchiness much more effectively than either steroids or antihistamines alone, and at much lower doses. Topical preparations containing hydrocortisone and Pramoxine are often prescribed for isolated, irritated areas of skin. They are quite effective in providing temporary relief from itching and pain.

In some cases, allergen-specific immunotherapy (also called hypersensitization) can help dogs suffering from atopy. This treatment is usually reserved for those dogs that do not respond sufficiently to other forms of medical management. Hypersensitization involves a series of subcutaneous injections of gradually increasing doses of allergens that are present in the dog’s environment and that cause positive reactions on the dog’s intradermal allergy skin tests. This therapy is helpful in about 70% of the cases, as the dogs become desensitized to the environmental allergens over time (usually 9 to 12 months of treatment or longer). Hypersensitization normally is used when it is desirable to avoid or reduce the amount of steroids being given, when clinical signs last longer than 4-6 months despite other treatment, or when other forms of antipruritic therapy do not provide sufficient relief. The response to allergen-specific immunotherapy is usually slow, taking 6 to 12 months in most cases.

Physical restraint by use of Elizabethan (cone or “lampshade”) collars, foot bandages, T-shirts, sweat shirts or canine booties may be helpful in reducing self-inflicted trauma, although they will not reduce the itchiness that predisposes affected dogs to chewing, licking, scratching and biting. Finally, dietary management can greatly reduce the symptoms of atopy in some dogs by switching to a higher-quality food, even in the absence of an identifiable food allergy.

Prognosis

Owners of dogs with atopy should recognize that environmentally-caused allergies are likely to affect their dogs for life. However, with patience, individualized treatment, good communication and cooperation between owners and the medical team, virtually all cases of atopy can be well-managed. Routine veterinary examinations, at least twice a year, are important to long-term control of this condition, especially for dogs on long-term corticosteroid or other pharmaceutical therapy.

Diagnosis and Tests