Allergies are a common cause of skin and ear conditions in dogs. Dogs with allergies rarely show signs that are similar to people, who develop hay fever (sneezing, watery eyes, runny nose).
Dogs usually suffer from red and itchy skin, hair loss and recurring skin or ear infections. There are three major causes of allergies in dogs including:
- Food Allergies
- Atopic Dermatitis (environmental allergens)
- Flea Allergy Dermatitis (the most common here on Vancouver Island)
Flea allergy dermatitis is the most common skin disease we see here at Van Isle Veterinary Hospital in dogs. You may not see fleas… but that doesn’t mean those pesky creatures are not there! Flea allergies are caused by flea saliva, and it only takes a few bites to cause a major problem. As lucky as we are to live in a relatively mild climate in the Comox Valley, this means that fleas may survive year round in low numbers. If a dog has flea allergies, 100% flea control is necessary to prevent symptoms. This may mean year-round flea prevention therapy to reduce the itch
Some dogs will develop allergies to foods. Potential food allergies include proteins, carbohydrates, preservatives or dyes. The only way to accurately diagnose a food allergy is to put your dog on a prescription or homemade hypoallergenic diet for a minimum of 4-6 weeks. The diet must only contain ingredients that your dog has never eaten before. This is called a diet trial. In order to have a successful food trial, your dog cannot eat any other food, treats, dental sticks or table scraps! If the allergy signs resolve, the former diet is offered to your dog, and if the itching returns, a food allergy is diagnosed.
Atopic dermatitis is an inherited predisposition to overreact to a variety of commonplace substances in the environment. These allergens include plant pollens, house dust mites or mold spores. Our damp, rainy winters and yearlong green foliage can contribute to allergy symptoms in our patients that persist over the winter. In other regions of Canada, this type of allergy may present as more of a seasonal irritation. That being said, we will sometimes see an increase in atopic dermatitis symptoms in the spring or in the fall. Most dogs with this type of allergy begin to show symptoms between 1 and 3 years of age. Diagnosis of atopic dermatitis is made based on results of intradermal skin testing or by in vitro blood testing. This may require referral to a veterinary dermatologist and is often recommended if we see no response to flea treatments or diet trials and there are no significant findings on routine blood tests.
If a dog is diagnosed with atopic dermatitis, there are three methods of treatment:
- Avoidance of allergens (if possible)
- Frequent bathing with a medicated shampoo to remove contact allergens
- Oral Medications (including antihistamines, steroids, cyclosporin and oclacitinib)
Some dogs may develop side effects to certain medications and not every medication works for every dog. Allergen-specific immunotherapy is the third method of treatment and has a 60-80% success rate but may take months to take effect. Although therapy may be decreased in frequency over time, it is usually considered a lifelong treatment.
Allergies are also often the cause of secondary recurring skin and ear infections. Bacterial and yeast infections can increase your dog’s itchiness. Medicated bathing or long term antibiotic and anti-yeast medications may be recommended.
Unfortunately, allergies are usually a life-long incurable problem.
As veterinarians, we strive to control allergies as best we can and improve the quality of life for you and your dog. Coping with allergies can be extremely frustrating for our patients, their owners and their veterinarians. The best we can do is work together to diagnose the underlying cause to try to reduce the need for medications and allow us to use more specific allergy treatments… and most importantly to give your dog the best chance for a comfortable, happy life!
Submitted by Dr. Yvette Maclean – Van Isle Veterinary Hospital.