New Therapies For Allergic Dogs

By Teresa Garden, DVM

Atopy (atopic dermatitis) affects 10 – 15% of dogs. Genetics play a role. The following breeds are predisposed and if have allergies should not be bred: Terriers, Setters, Beagles, Boxers, Lhasa Apsos, Bulldogs, Miniature Schnauzers, Retrievers, Dalmations, and German Shepherds. Age of onset for atopy/allergy is 6 months to 3 years for 75% of allergy patients. Clinical signs are an itch that rashes affecting the face, ears, feet, legs, axillary and inguinal regions. Allergens are absorbed percutaneously. Dogs born in May and December have a higher risk factor for developing atopy. Vaccinations and over-vaccination may precipitate the disease.

Fortunately, there are a couple of new drugs recently brought to market to treat atopy and improve the quality of life for our allergic dogs. These drugs are safer, targeted, and more effective than previous treatments we could offer. Apoquel (oclacitinib) is a synthetic Janus kinase inhibitor. It is a completely different class of drug than steroids or antihistamines and has been on the market since 2013. Apoquel works by blocking Interleukin-31 (IL-31). IL-31 is the cytokine linked to itching and inflammation brought on by allergies. Apoquel can suppress other Interleukins involved in allergy, inflammation and pruritis such as IL-2, IL-4, IL-6, and IL-13. Apoquel has an immediate benefit to the patient. Itching decreases dramatically within 1 to 4 hours of receiving the drug. Some patients take longer to respond (7 days). Clinical studies show 85% of dogs will respond favorably. Apquel cannot be used in dogs less than 1 year old or in breeding dogs. Blood profiles should be done every 3 months during the first year the patient receives the drug. Exams should be conducted periodically to rule out any underlying bacterial or yeast infections while the dog is taking the drug.

Another new product has become available to veterinarians within the past year. Canine Atopic Dermatitis Immunotherapeutic (CADI) is a once a month injection of a monoclonal antibody designed to target IL-31. It’s trade name is now Cytopoint. Side effects with Cytopoint are extremely uncommon. Cytopoint can be given to puppies and dogs with other health problems. It can be used in dogs that did not respond to Apoquel. Onset of action is within 24–48 hours post-injection. It is highly specific and, therefore, has minimal side effects. In some dogs its antipruritic effect may last up to 3 months. It has been shown to be effective in 80% of patients.

Supportive therapies for atopy can improve outcomes and enhance quality of life for our pets. Probiotics such as Proviable will boost T-helper cells in the body and allow the dog to become less prone to develop atopic dermatitis. Dermatologists have advised starting at-risk breeds on Proviable as puppies. Fatty acid supplementation plays a positive role in the treatment of atopy. Omega-3 fatty acids will compete with omega-6 fatty acids in metabolism. This results in production of less inflammatory cytokines and may also down regulate inflammation. Nordic Naturals Omega-3 Pet and Grizzly’s Salmon Oil are good brands to consider for use.

Skin barrier repair products help many of our atopy patients. These products improve skin barrier function by replacing missing ceramides and other fats in the lipid bi-layers of epidermis. Dermoscent is a topical treatment to be applied to a few spots on the skin and then it will diffuse. Duoxo shampoo, spray, or mousse products can also help to repair the thinning lipid membrane.

Daily cool water baths with oatmeal shampoo is a staple of treatment for many dogs. Cool water will give relief from itching and inflammation. Bathing removes surface debris, allergens, bacteria and irritants. Combining daily baths with antihistamines may give many patients significant relief from itching. Antihistamines block H1 and H2 receptors to decrease itch. They also have a mild sedative effect which can decrease anxiety associated with pruritis. Common antihistamines used in dogs are Benadryl, Tavast, hydroxyzine, and chlorpheneramine. It is best to start them early in the allergy season and give them consistently for the best effect.

Immunotherapy is considered the “gold standard” of allergy treatment. Immunotherapy allows us to modulate the allergic response without drugs. Immunotherapy, based on intradermal skin testing, is tailored to each individual dog. Therapy can be in form of subcutaneous injections or oral medication. Both enjoy a 70-90% success rate when based on skin testing. The best time to test is the end of allergy season when IgE antigens are highest. Significant benefits are usually seen by 8 to 9 months of therapy. Most dogs will require therapy for life although 25% will experience a cure.

Future therapies will continue to be targeted, safer, and even more effective in helping our allergic dogs. Antibody regulation, DNA vaccines, and antimicrobial peptides are just some of the promising treatments on the horizon for atopy patients.

Dr. Teresa Garden is chief veterinarian/owner of Animal Health & Healing, a full-service holistic and conventional veterinary practice in the Maplewood/Richmond Heights area. 314-781-1738. www.AnimalHealthandHealing.com.