By Julia Robson from DogsPlanet

Nothing can be quite as frustrating or exhausting for pet parents as dealing with a very itchy dog.  As a small animal veterinarian, I regularly diagnose and treat dogs suffering from a bad case of pruritus (i.e., itchiness) and allergies.  While there are many reasons that dogs might experience allergic skin disease, perhaps the most difficult to handle is canine atopic dermatitis. 

This article covers everything you need to know about atopic dermatitis in dogs so you can quickly recognize the symptoms of atopy in your pet, reduce your pet’s risk of flare-ups, and understand how atopic dermatitis is treated and managed if your pet is affected by the troublesome disease.

What is Atopic Dermatitis in a Dog?

what is atopic dermatitis in dogs

Canine atopic dermatitis, or atopy, is a chronic, inflammatory skin condition driven by underlying allergies.  In dogs affected with atopy, the immune system is hypersensitive to commonplace and otherwise harmless substances in the environment.  The most common allergens behind atopic dermatitis include plant pollen, house dust, dust mites, mold spores, animal dander, and insect bites, but any environmental allergens can be the cause. In a way, these pets are practically allergic to themselves!

The overreacting immune system upregulates inflammation in the skin, leading to a very itchy, uncomfortable dog and a reduced quality of life. Over time, the inflammation leads to a compromised or weakened skin barrier, which allows for the development of secondary skin infections. In addition, the ears are also affected by these changes leading to itch, pain, and infection of the ears. These 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 / Symptoms of Atopic Dermatitis

signs and symptoms of atopic dermatitis in dogs

Atopic dogs usually begin to show signs of the disease as early as 6 months to 6 years of age, although exposure to a new environment can trigger the disease in an older dog.  Typically, atopic dermatitis 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, and/or scooting
  • Red, irritated skin 
  • Thickened, elephant-like skin
  • Hyperpigmented (darker) skin
  • Dry, crusty, flakey skin
  • Oily, greasy skin patches 
  • Alopecia or hair loss
  • Red, painful ears
  • Goopy or watery eyes
  • Unpleasant odor from the skin and/or ears 
  • Open wounds and scabs
  • Chronic or repeated skin and ear infections

The entire body is affected, but symptoms are often most severe in the armpits, groin, lower abdomen, paws, ears, and muzzle. 

Causes of Atopic Dermatitis

Although the exact cause of canine atopic dermatitis is unknown, it does appear to have a genetic predisposition and is considered hereditary.  For this reason, dogs who are affected by atopy should not be bred to avoid passing the disease on to future generations.  Several breeds of dogs 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, Pitbull mixes, Lhasa Apsos, Dalmations, 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 severe allergic reactions and hypersensitivity to environmental allergens.  Unfortunately, dogs who are affected by environmental allergens may also be affected by other allergens such as flea allergy dermatitis or food allergies, which can upregulate the amount of itch and irritation dogs with atopy experience.  Read more about other causes for itching here.

In some atopic dogs, the disease has seasonal tendencies, meaning that their signs of atopic dermatitis are worse during some seasons than others. For example, dogs who are allergic to pollen are likely to feel more itchy in the spring when plants are blooming than they do in the winter.  

Diagnosis of Atopy

While a detailed history and a thorough physical exam can point your veterinarian in the direction of atopy, testing is important to ensure your pet is not misdiagnosed resulting in wasted time and resources.  

Atopic dermatitis is considered a diagnosis of exclusion, which means that other types of allergies must be ruled out before your veterinarian can definitely determine that atopy is the cause of your dog’s itchy skin. 

Ruling out Parasites and infections

First and foremost, your veterinarian will need to rule out parasites and infections as the cause.  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 severely allergic or hypersensitive to flea bites than others.  Therefore, any dog displaying signs or symptoms of allergic skin disease must be started on a prescription grade, high quality flea preventative medication, if they are not already receiving one.  A skin scrape to check for mites, such as demodex, is also important to ensure that this infection is treated if present, otherwise treatment will fail. 

Next, any secondary skin infections or ear infections that are present must be addressed since they are adding to the level of itch atopic dogs experience.  Samples will be taken from the affected skin, ears, and/or nail beds and examined under a microscope, referred to as cytology.  Cytology allows the veterinary team to determine if these are bacterial infections or yeast infections so the appropriate medications can be prescribed.  In some cases, hair plucking and culturing to check for ringworm, or dermatophytosis, may be recommended. 

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.

If the itch is still present once parasites and infections are identified and treatment is initiated, starting a strict diet trial to determine if your dog is affected by food allergies is recommended.  While only about 10% of dogs with allergic skin disease are hypersensitive to food allergens, some dogs are affected by both food and environmental allergies. 

While blood testing (i.e., serological testing) for food allergens is an option, results are considered unreliable.  An 8-12 week diet trial is the gold standard for identifying canine food allergies and intolerances properly.

After all the above tests have been performed and other types of allergies addressed and ruled out, a diagnosis of atopic dermatitis is established.  Further testing can be used to 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 with 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 pet's allergic reaction. This type of test 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 reaction, and measurements of any reactions are recorded.  For more information on allergy testing, see our article, “Ditch the Itch: What to Expect from Dog Allergy Testing.”

Since these types of tests are expensive, in many cases, treatment for atopic dermatitis may be initiated without advanced allergy testing. 

Treatment

treatment of canine atopic dermatitis

Since allergies cannot be cured, they must be continuously managed; therefore, treatment for canine atopic dermatitis is necessary life-long.  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). 

Signs of Allergic Skin

Any dog displaying signs or symptoms of allergic skin disease must be started on a prescription grade, high-quality flea preventative medication if they are 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 itch in atopic patients. 

Dogs suffering from secondary skin and ear infections will require antibiotic and/or antifungal medications.  Skin infections, whether bacterial or fungal in nature, are best treated from the outside and the inside.  Expect to treat the infections with a combination of oral medications and topical medications such 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 hair coat, soothes injured skin, and calms inflammation.  The shampoo should contain antimicrobial and antifungal agents as well as ingredients that soothe the skin and allow the skin to be bathed on a more frequent basis without drying it out.

Dermatitis due to food allergies

Atopic dogs diagnosed with food allergies may need to eat a prescription hypoallergenic diet. In dogs, the immune system mounts an allergic response to proteins in the food, namely those from chicken, beef, or soy.  Veterinary prescription diets are formulated with hydrolyzed proteins, which are proteins that have been separated into smaller components so as not to trigger the immune system.  These diets are manufactured under the strictest quality control measures to ensure there is no cross-contamination by other ingredients.

Since canine atopic dermatitis is driven by chronic inflammation, anti-inflammatory medications are the mainstay of treatment.  These drugs include antihistamines, corticosteroids, cyclosporine, and newer, safer drugs such as oclacitinib (Apoquel) and lokivetmab (Cytopoint).  Every dog is different, so different anti-allergy medications may need to be tried as not every medication works in all pets.  While steroids are an affordable option, they are not recommended for chronic use as there are many detrimental side effects when given long-term.  Most atopic dogs require a combination of different anti-inflammatory/anti-allergy medications to achieve the best control of their clinical signs.  

For dogs who were tested for specific allergens via serology or intradermal skin testing, allergen-specific immunotherapy can be initiated.  After the allergens for a specific dog are identified, a mixture of the antigens can be formulated into a hyposensitizing injection (allergy shot). These injections make the dog less sensitive to their allergens.  While immunotherapy is successful in 60-80% of patients, it may take immunotherapy several months to have any effect.  If the injections are helpful, they can be safely continued lifelong.  

Dietary supplements, such as Native Pet’s Allergy Chews, provide even more anti-inflammatory, antihistamine, and immune-boosting properties for allergic pets. It supports your dog's immune system with spirulina, an algae that offers anti-inflammatory benefits, and colostrum, an ingredient packed with nutrients and antibodies that are known to support immune health. These products won’t replace necessary medications, but they are great complementary agents to any atopic dermatitis treatment plan. Other dietary anti-inflammatory supplements, such as Native Pet’s Omega Oil, can also help to reduce inflammation of the skin.  Essential fatty acids like omega-3 and omega-6 fatty acids are natural anti-inflammatory and antioxidative agents with virtually no side effects.  Canines best absorb fatty acids derived from a source of fish like salmon or cod.  

Prevention 

Unfortunately, there’s no way to prevent your dog from developing allergies.  For pet parents considering buying a new puppy, ask the breeder about any hereditary conditions the dam and sire may carry.

Summary

atopic dermatitis care and precautions

Atopic dermatitis in dogs is a frustrating, taxing disease for both affected pets and the people who love them.  Fortunately, excellent treatment options are available, and treatment plans can be customized to meet each specific pet’s needs.

While you cannot prevent atopic dermatitis in your dog, by arming yourself with knowledge of the disease you can recognize the clinical signs of atopic dermatitis and know what to do and what to expect should your dog develop this life-long, inflammatory skin condition.   

Frequently Asked Questions about Atopic Dermatitis in Dogs

What is atopic dermatitis?

Atopic dermatitis is a disease in which the dog suffers from chronic inflammatory and pruritic skin allergies. This disease is hereditary.

What are the symptoms of atopic dermatitis?

These are the symptoms of atopic dermatitis.

  • Scratching, chewing, licking, rubbing, or scooting
  • Red, irritated skin
  • Thickened, elephant-like skin
  • Hyperpigmented (darker) skin
  • Dry, crusty, flakey skin
  • Oily, greasy skin patches
  • Alopecia or hair loss
  • Red, painful ears
  • Goopy or watery eyes
  • Unpleasant odor from the skin or ears
  • Open wounds and scabs
  • Chronic or repeated skin and ear infections

Why is atopic dermatitis caused?

The exact cause of atopic dermatitis is not known. Anyhow, the disease is considered hereditary. Some dogs display severe symptoms in specific seasons. During other seasons they do not have any sign.

What are the precautions one should take for atopic dermatitis in their dog?

The most important precaution that needs to be taken is to manage the disease with proper and timely medication. It would be best if you prevented the dog from all the situations which can aggravate the symptoms. Atopic dermatitis in dogs is a genetic disease, and the owner will have to manage the condition for the dog's entire life.

Is atopic dermatitis curable?

No. There is no cure for atopic dermatitis. Although, if the pet owner takes extra care, they can manage the disease and prolong the span and quality of the dog's life.

How do you treat atopic dermatitis in dogs?

The treatment of canine atopic dermatitis includes medicated baths, antihistamines, antibiotics, flea control, supplements like omega oil and allergy chews, hypoallergenic diets and immunotherapy

What does atopic dermatitis look like in dogs?

A dog suffering from atopic dermatitis will scratch various parts of its body and can face hair loss. The animal might rub or lick its feet, ears, armpits, or groin. Sometimes they might even bite or scratch. The part of the body that is scratched consistently loses hair, and the skin there becomes hard. The skin dries and forms crusts.

Are there any home remedies for atopy?

There are no home remedies that are highly effective. Anyhow, oatmeal can give some relief in the consistent itch. It is good for the skin and can help in controlling dryness.

What do you feed a dog with atopic dermatitis?

You can feed your dog with prescription diets that are formulated with hydrolyzed proteins. You should also avoid feeding it any food that can trigger allergy.


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