By Dr. Hammond, DVM (@thehonestvet)
For pet parents, dealing with an itchy dog can be difficult and disheartening. And yet, it’s one of the more common conditions to affect otherwise healthy dogs. Most small animal veterinarians regularly diagnose and treat dogs and cats suffering from a bad case of pruritus (itchiness). While there are many reasons that dogs might experience itchiness, one of the main causes — and perhaps the most difficult to address — is atopic dermatitis in dogs.
Atopic dermatitis in dogs is typically brought on by allergies, and pruritus is one of its main symptoms. While it can be a difficult condition to initially get under control, there are effective treatment options that can dramatically improve your dog's quality of life.
We'll cover everything you need to know about canine atopic dermatitis. Below, you'll learn to quickly recognize the symptoms of atopy in your pet, reduce your pet’s risk of flare-ups, and understand how your vet can help you treat and manage atopic dermatitis in dogs.
What Is Atopic Dermatitis in Dogs?
Canine atopic dermatitis, also known as allergic dermatitis or atopy, is a chronic, inflammatory skin condition caused by underlying allergies. In allergic dogs, the immune system is hypersensitive to common and otherwise harmless substances in the environment.
The most common dog allergies include plant pollen, house dust mites, mold spores, animal dander, and insect bites. But exposure to any environmental allergens can cause atopic dermatitis in dogs.
In this condition, a dog’s overreacting immune system produces an immune response to an allergen that increases inflammation in the skin. This leads to a very itchy, uncomfortable dog and reduces the quality of life of your pet.
Over time, the inflammation leads to a compromised or weakened skin barrier, which can lead to secondary skin infections. Some of the most common secondary infections include pyoderma (skin lesions), Staphylococcus intermedius (staph infections), and Malassezia pachydermatis (yeast infections).
In addition, the ears are often affected, leading to itch, pain, and infection of the ears. These secondary infections make the itchy skin and ears even more irritated and inflamed, and the result is an endless cycle of itch, irritation, and infection.
Signs and Symptoms of Atopic Dermatitis
Atopic dogs usually begin to show signs of the disease between six months and six years of age, although exposure to a new environment can trigger the disease in older dogs. Typically, atopic dermatitis in dogs begins with mild signs that become worse over time.
Dogs with atopic dermatitis display one or more of the following clinical signs:
- Scratching, chewing, licking, rubbing, or scooting
- Red, irritated skin
- Thickened, elephant-like skin
- Hyperpigmented (darker) skin
- Dry, crusty, flaky skin
- Oily, greasy skin patches
- Alopecia, or hair loss
- Red, painful ears
- Goopy, watery eyes or conjunctivitis
- Unpleasant odor from the skin or ears
- Open wounds, scabs, or skin lesions
- Chronic or repeated skin and ear infections
The entire body is affected, but symptoms are often most severe around the armpits, groin, lower abdomen, paws, ears, and muzzle.
Causes of Atopic Dermatitis in Dogs
Although the exact cause of canine atopic dermatitis is unknown, dogs can have a genetic predisposition for it, and the condition is considered hereditary. For this reason, dogs that are affected by atopy should not breed to avoid passing the disease on to future generations.
Several dog breeds are predisposed to atopic dermatitis and allergies, including golden retrievers, Labrador retrievers, West Highland white terriers and other terrier breeds, Irish setters, Shih Tzus, Chinese shar-peis, English bulldogs, French bulldogs, boxers, beagles, pit bull mixes, Lhasa apsos, Dalmatians, and Olde English Sheep Dogs. However, any breed of dog, including mixed breed dogs, can be plagued with atopic dermatitis.
As discussed, atopic dermatitis is driven by allergic reactions and hypersensitivity to environmental allergens. Unfortunately, dogs affected by environmental allergens may also be affected by other allergens such as flea allergy dermatitis or food allergies, which can increase the amount of itch and irritation dogs with atopy experience.
In some atopic dogs, the disease has seasonal tendencies, meaning that their atopic dermatitis may be brought on by seasonal allergies. This means their symptoms will be worse during some seasons than others. For example, dogs allergic to pollen are likely to feel itchier in the spring when plants are blooming.
Diagnosis of Atopic Dermatitis
Atopic dermatitis is considered a diagnosis of exclusion, which means that other types of allergies must be ruled out before your veterinarian can determine that atopy is the cause of your dog’s itchy skin.
While a detailed history and a thorough physical and dermatologic exam can point your veterinarian towards atopy, testing is essential to ensure your pet is not misdiagnosed, resulting in wasted time and resources.
Ruling Out Parasites and Infections
First and foremost, your veterinarian will need to rule out parasites and infections. Your vet will take a skin scrape to check for mites and will use a flea comb to check for fleas. Even if you haven’t seen any fleas, a single flea bite can leave a dog itching and scratching for days, and some dogs are more allergic to flea bites than others.
Therefore, any dog displaying signs or symptoms of allergic skin disease will need to start taking a prescription-grade flea medication if they’re not already receiving one. This medication should be given year-round, including in the winter.
Even if fleas are not the root cause of your dog’s itchy skin, strong flea control is critical to avoid flare-ups of itchiness in atopic patients. In addition to prescription flea medicine, your dog may also benefit from home remedies for fleas.
Testing for Secondary Infections
Next, your vet will need to address any secondary skin infections or ear infections since they add to the level of itchiness that atopic dogs experience. To diagnose secondary infections, samples will be taken from the affected skin, ears, and nail beds and examined under a microscope. This is referred to as cytology.
Cytology allows the veterinary team to determine if these are bacterial or yeast infections so they can prescribe the appropriate medications. In some cases, hair plucking and culturing to check for ringworm, or dermatophytosis, may also be recommended.
Dogs suffering from secondary skin and ear infections will require antibiotics or antifungal medications. Whether bacterial or fungal, skin infections are best treated from the outside and the inside. Expect to treat the conditions with a combination of oral medications and topical medications such as medicated shampoos, medicated sprays, medicated mousse, ear cleansers, and ear drops.
Medicated baths and regular ear cleaning should be continued even after infections have resolved. Bathing weekly or every other week removes allergens from the coat, soothes injured skin, and calms inflammation. The shampoo should contain antimicrobial and antifungal agents and ingredients that soothe the skin and allow the skin to be bathed on a more frequent basis without drying it out.
Ruling out Underlying Disease
Since the thyroid hormone plays a crucial role in maintaining a healthy skin barrier, dogs displaying signs and symptoms of atopic dermatitis should also be screened for hypothyroidism. Your veterinary team will take blood samples from your dog to measure their total thyroid levels.
Testing for Food Allergies
If the itch is still present once parasites and infections are identified and treated, you may need to start a strict diet trial to determine if your dog has food allergies. While only about 0.2% of dogs are hypersensitive to food allergens, some dogs are affected by food and environmental allergies.
While blood testing (i.e., serological testing) for food allergens is an option, results tend to be unreliable. An 8-12 week diet trial is the gold standard for correctly identifying dog food allergies and intolerances.
Testing for Environmental Allergies
After all the above tests have been performed and other types of allergies have been addressed and ruled out, a diagnosis of atopic dermatitis can be established.
Further dog allergy testing can identify what a pet is allergic to in the environment. There are two ways to test for environmental allergies: serological testing (i.e., blood tests) or intradermal allergy testing.
Serologic allergy testing is cheaper and can be performed by your regular veterinarian. However, the results are not always reliable, and the quality of this test depends on the laboratory that analyzes the results.
Therefore, leading veterinary dermatologists recommend intradermal testing to identify the cause of your dog’s skin allergies. Intradermal skin testing is performed by shaving the fur on one side of the chest and injecting small amounts of common allergens into the dog’s skin. The skin is then observed for a cutaneous reaction, which is a skin reaction such as redness, inflammation, or hives, and any responses are recorded.
Since these types of tests are expensive, in many cases, your vet will start treatment for atopic dermatitis without advanced allergy testing.
Treatment Options for Atopic Dermatitis in Dogs
While there isn’t a cure for atopic dermatitis in dogs, there are several treatment options that can help reduce or eliminate your dog’s symptoms. These options include:
- Medicated baths
- Immune-therapeutic drugs, like cyclosporine, oclacitinib (Apoquel), and lokivetmab (Cytopoint)
- Oral or topical steroids, including corticosteroids like prednisolone or glucocorticoids
- Flea control
- Supplements, including fish oil and allergy chews
- Limited ingredient diets
- Allergen-specific immunotherapy, also known as hyposensitization
Since allergies cannot be cured, they must be continuously managed. Therefore, treatment for canine atopic dermatitis will continue throughout your dog’s life. The goal of treatment is to control clinical signs and avoid flare-ups of dermatitis (inflamed skin), moist dermatitis (hot spots), and otitis (inflamed ears).
Every dog is different, so different anti-allergy medications may need to be tried. Not every medication works on all pets. Dietary supplements provide even more anti-inflammatory, antihistamine, and immune-boosting properties for allergic pets. These products won’t replace medication, but they're a great complement to any atopic dermatitis treatment plan.
Native Pet’s Allergy Chews support your dog's immune system with spirulina, an algae that offers anti-inflammatory benefits, and colostrum, an ingredient packed with nutrients and antibodies that help support immune health.
Other dietary anti-inflammatory supplements, such as Native Pet’s Omega Oil, can also help to reduce inflammation of the skin, as omega 6 is an essential fatty acid. Essential fatty acids are natural anti-inflammatory agents with virtually no side effects.
Help Your Dog With Atopic Dermatitis
Atopic dermatitis in dogs is a frustrating, taxing disease for both affected pets and the people who love them. It can take time to diagnose because your veterinarian will have to rule out other potential causes first.
Because there’s no one-size-fits-all treatment plan, you and your vet will also need to work together to test and adjust your dog’s medication until you find the best option for your pet. Fortunately, excellent treatment options are available, and treatment plans can be customized to meet your pet’s specific needs.
While you can’t prevent atopic dermatitis in your dog, by arming yourself with knowledge of the disease, you can recognize the clinical signs of atopic dermatitis in dogs and know what to do if your pet suffers from this inflammatory skin condition. You can help keep your dog comfortable in the face of this uncomfortable condition.
For more information on your dog’s health and wellness, visit the Native Pet blog.
About the Author: Dr. Hammond received her Doctor of Veterinary Medicine degree from Texas A&M University College of Veterinary Medicine and currently practices as a general practice and emergency veterinarian in Charleston, South Carolina.