AKC through the Canine Health Foundation recently offered a free webinar on itchy dogs by Dr. Andrew Hillier BVSc MANZCVS DACVD. Dr. Hillier felt there are some main causes of itching in dogs – infections including parasites such as fleas and mange as well as bacteria and yeast, food allergies and environmental allergies such as atopy.
From a parasite point of view, Dr. Hillier felt that fleas, and their associated flea allergy, were one of the big causes of itching in dogs. A dog with flea allergy just needs one flea bite to lead to a major itching, digging reaction. He pointed out that families need to not only treat the dog involved, but also all other pets plus the environment. He stressed that with all of the new weapons in the flea fighting arsenal, that people should be able to conquer this problem. One of his first steps in working up an itchy dog is to verify that there is flea control.
Infections tend to develop in unhealthy skin – generally secondary to parasite infections, food allergy or other allergies. Medications including antibiotics or antifungals, plus shampoos and topicals can help clear up infections but unless the underlying cause of the itching and chewing is addressed, the infections will return.
Food allergies are not that common in dogs as opposed to food intolerances. Blood tests are better for picking up intolerances than for finding true food allergies. Ear problems are classic for pets with food allergies. Dr. Hillier felt that the only way to get to the bottom of a food allergy situation was to do a feeding trial with limited protein source for 6 to 8 weeks. That means the entire diet has to be controlled, including treats. He also felt that prescription diets with limited proteins were by far the best option.
Many itching dogs have varying degrees of atopy or environmental allergies. These dogs classically chew their feet, rub their faces and dig and chew in the groin area. Often the itching starts out seasonally though it may progress to all year round. A dog with pollen allergy may stay seasonal, while a dog with dust mite allergies may progress to all year. Dr Hillier felt dust mites were possibly the biggest source of allergies in dogs. It is important to remember that allergies are a “threshold” disease. Your dog’s immune system may have no trouble handling a dust mite allergy but when pollen season comes along his system is now overwhelmed and you get clinical signs of allergies. Atopy does seem to have a genetic component but also requires environmental exposure. For example, a dog who is allergic to palm trees may never itch if he lives in Alaska.
Treating allergies can be complicated. Veterinarians try to avoid prednisolone and prednisone due to side effects on both health and behavior. Some dogs show aggression and/or resource guarding when on these medications. In addition, many dogs drink more and need to go out to urinate more frequently. Liver and adrenal complications can show up with long term use. A better solution is to determine which allergens are most important to your dog and developing customized hyposensitization therapy via injections or oral drops. Topicals such as shampoos and sprays may also help. Antihistamines help some dogs especially if given right at the start of any clinical signs.
When asked what he felt was the least helpful to dogs with itching problems, Dr. Hillier noted four things. He felt that using a raw diet and/or changing to a grain free diet was of limited help. He stressed that over the counter flea products were not as safe or effective as products purchased from your veterinarian. Fatty acid supplements were also not considered to be very effective – though many diets already contain them, so perhaps additional ones were just wasted. In his experience, antihistamines were also of limited use – perhaps because the dog’s condition tended to be advanced when these were tried.
Itching dogs can be very frustrating for owners and veterinarians to treat. Taking any prolonged itching seriously can mean greater luck in treatment as you catch the cause early on.