High on the list of most common things pet parents ask us about at PetCoach is allergic disease. Allergies are easily one of the most frustrating problems dog and cat owners deal with. They’re often expensive to treat, require repeated visits to the vet (and sometimes even to veterinary dermatologists), and left uncontrolled will seriously decrease your dog’s quality of life.
The cause of allergic disease is not well understood. For some reason some individuals have a wildly exuberant immune reaction to something that’s routinely found in the environment – something that the vast majority of other dogs have no problem with being exposed to.
The substance that’s inciting this reaction can be something in the environment that’s breathed in – like pollen, dust, and even cat dander. It can also be something in the food that the dog eats. The main inciters tend to be beef, chicken, corn, and wheat – ingredients that tend to be in most commercial pet foods.
Most dogs are either allergic to something inhaled or something in their food. An unlucky few, about 10% of all allergic dogs by some estimates, have allergies to both. What are the most successful strategies for getting your dog some relief? Read on to find out.
Treat the symptoms
Canine atopy (allergic skin disease) usually has a very common pattern that looks similar in all allergy sufferers. While they can be itchy all over, the most intense symptoms occur under the armpits (axillae), in the groin region (inguinal), and on the skin of the abdomen. Many dogs also get chronic ear infections that are difficult to treat and recur frequently.
When it’s determined that a dog has allergies most owners decide to treat the symptoms. The most successful approach is multi-faceted and involves using medications, supplements, and topical products for the most severely affected individuals.
The last ten years have seen some really valuable advancements in the drugs we have available to treat allergic disease. In the past the only alternative was immunosuppressive drugs like prednisone, which while very effective in stopping the immune system’s reaction to the allergen has significant and potentially dangerous side effects over time. Newer drugs, like Atopica and Apoquel, both of which also stem the immune response but in different ways, are extremely effective and have fewer side effects.
Fish oils are a mainstay of therapy for allergic disease. Used at high doses, these omega-3 fatty acid containing therapies have anti-inflammatory properties, and also work to calm itchy skin. In addition, omega-3 fats are an important component of healthy skin, so they can actually work to rebuild the skin barrier that is often broken down with chronic scratching and secondary skin infections.
Topical therapies like shampoos, conditioners, and lotions that contain colloidal oatmeal and the topical anesthetic pramoximine are useful in calming itchy skin, but they typically don’t do the complete job alone.
Tackle the problem at the source
There’s no real “cure” for allergies, but the closest we can come is to de-sensitize the immune system to whatever is setting it off. This means first figuring out what that is. Allergy testing involves injecting small amounts of a number of common allergens – dust mites, cat dander, grass pollen, hay, etc. – into the space just under the skin, the dermis. A “control” is also established by injecting sterile water at one location.
If there is swelling at the site of injection of a substance, it’s likely that there is an allergy to that substance. It’s great to know what your dog is allergic to, but the idea that your dog can spend the rest of its days avoiding something as ubiquitous as grass, for example, is a little absurd. So most people go on to purchase and give (or have their vet give) what are called hyposensitization injections. These are specially formulated for each individual, incorporating ever-increasing amounts of what that dog is allergic to. The shots are given at specific intervals in time, increasing in frequency and amount of allergen, until the dog’s immune system has gradually been conditioned to the allergen.
The dog will have to continue to receive the injections for its entire life. It takes an average of nine months to one year of injections to see noticeable improvement in allergic signs. Most dogs need additional treatments during this time to calm the allergic signs and make them more comfortable.
Change the diet
While most dogs have environmental allergies, some are allergic to the ingredients in their food. These allergies can manifest as itchy skin problems, but many dogs with food allergies have recurrent diarrhea and vomiting. Some also have problems with their anal glands, and any dog that has recurrent anal gland issues should undergo a trial with hypoallergenic dog food.
There are two main types of hypoallergenic foods. The first hypoallergenic diets developed used what are called novel proteins and novel carbohydrates. The word “novel” in this case indicates that these ingredients typically aren’t components of pet foods, and thus allergic dogs won’t have an allergy to these foods. These diets usually contain duck, venison, fish, or rabbit as the protein source, and potato or sweet potato as the carbohydrate source.
More recently, in an attempt to make foods that don’t rely on such difficult to obtain ingredients, hydrolyzed diets have become more popular. The process for making these foods involves creating proteins that are too small to be recognized by the immune system from a commonly available protein source like chicken.
When it’s suspected that a dog is allergic vets will often recommend a food trial to start with, in order to see if the pet improves on a novel or hydrolyzed diet. A true diet trial involves feeding only the hypoallergenic food – no treats or people food – for a minimum of six weeks. If improvement is complete, it’s likely that the dog only has food allergies. If improvement is partial, food allergies may be part, but not all of the problem. If there’s no improvement, the dog likely isn’t allergic to food.
Rule out other itchy things
Even if you think it’s completely impossible that your dog has fleas, mites (also known as mange), or ringworm, it’s important to rule them out. The biggest reason for doing this is that since treating allergic disease typically means suppressing the immune system, doing so will make it even more difficult for the dog’s own immune system to conquer an external invader, and he’ll likely get much, much itchier. Most vets will recommend a flea treatment, a skin scraping to look for mites, and a fungal culture to rule out ringworm before proceeding to treat or look for allergies.