Atopic Dermatitis (Atopy) in Dogs
Overview
Does your dog frequently experience excessive itchiness of the skin, paws, and ears? Perhaps they are also getting recurrent skin or ear infections, and despite treatment, their symptoms keep coming back. You may have even heard the dreaded word “allergies,” which can leave many pet parents with more questions than answers.
Dogs with atopic dermatitis, also known as atopy, develop an allergic skin condition which worsens over time. Living with a chronically itchy dog can be frustrating for everyone involved. Luckily, there are targeted treatment options that can help.
Let’s take a closer look at what causes atopy in dogs, symptoms to watch for, and how to help your dog manage this pesky skin condition.
What Is Atopic Dermatitis?
Canine atopic dermatitis is a common type of chronic allergic skin disease. It is estimated to affect 10-15 percent of dogs [5].
Specifically, it means that a dog has a genetic predisposition to developing red, pruritic (itchy) skin, most commonly due to environmental allergies [1]. A dog’s immune system responds to allergens that their skin is exposed to, that they inhale or, less commonly, that they ingest. Environmental allergens include pollen, dust mites, dander, and more.
Canine atopic dermatitis is a clinical diagnosis based on classic symptoms of red, itchy skin with a specific distribution over the body, and after ruling out other potential causes.
Causes of Atopy in Dogs
Any dog can develop atopic dermatitis, though some breeds seem to be more prone to it [1, 4]. These breeds include:
- Labrador and Golden Retrievers (including mixed breed Doodles)
- Pit Bull Terriers
- German Shepherds
- Dalmatians
- Boxers
- Shar-Pei
- Cocker Spaniels
- English Bulldogs
- French Bulldogs
- Pugs
- Many Terrier breeds, including Boston Terriers and West Highland White Terriers
The typical age of onset in dogs is between 6 months and 3 years [2].
Dogs who suffer from atopic dermatitis most commonly experience their first symptoms (age of onset) between 6 months and 3 years of age [2]. Aside from genetics and breed predisposition, other causes of atopic dermatitis in dogs include allergens like pollens, molds, and dust mites, which can trigger an immune system reaction. Dogs with atopic dermatitis may have a skin barrier that is not functioning properly, allowing allergens to penetrate the barrier and cause skin inflammation [1].
Atopic Dermatitis Symptoms
Atopic dermatitis in dogs most commonly causes excessive itchiness, which often results in redness and hair loss. It commonly causes secondary skin infections, and over time can cause chronic discoloration to the skin and hair.
Common symptoms of atopic dermatitis in dogs include:
- Excessively itchy skin (pruritus)
- Scratching, licking/chewing, and/or rubbing the skin
- Red skin
- Hair loss
- Occasionally, raised red bumps (papules)
- Brown staining to the fur (from saliva)
- Thickened, leathery texture to the skin
- Skin that is darker from chronic inflammation and/or yeast
Common complications of atopic dermatitis include recurrent ear infections, skin infections, and hot spots. Dogs with ear infections may shake or scratch at their ears, have brown odorous wax, and redness. Dogs with skin infections may experience progressive redness, hair loss, crusting/discharge, skin odor, increased moisture, raised red bumps that look like pimples (pustules), and worsening itchy skin.
Skin lesions commonly affect the paws (between the toes), face (around the lips/muzzle and eyes), ears, hairless regions (belly, armpits, groin), and legs (commonly on the front legs in front of the elbow) [1].
Dogs can have signs of atopic dermatitis seasonally or year-round, depending on what each dog is allergic to. Dogs with seasonal allergies may only have symptoms during certain months or seasons. A majority of dogs with seasonal atopic dermatitis will exhibit symptoms from spring through fall [2]. Many dogs with atopic dermatitis will progress to having year-round symptoms.
Diagnosing Atopic Dermatitis in Dogs
Your veterinarian will perform a thorough examination and take a detailed history to try to determine what is triggering your dog’s excessive itchiness and redness of the skin.
There is not a definitive test for atopic dermatitis. Instead, diagnosis involves ruling out other potential causes with similar signs, such as flea allergy dermatitis, food allergy, bacterial/yeast/fungal infection, and parasites like scabies or demodex. Your veterinarian will also check for secondary infections that can be caused by atopic dermatitis [1, 3].
Your veterinarian may conduct one or more of the following tests:
Skin cytology: This involves looking at skin cells or skin discharge with a microscope to check for skin infection (bacteria or yeast) or skin parasites. Bacterial and/or yeast infections frequently occur in dogs with atopic dermatitis. This is because itching and licking damages the protective skin barrier. These infections cause worsening in symptoms, making dogs even more itchy.
Ear cytology: This involves swabbing your dog’s ears and evaluating it under a microscope to check for ear infection (bacteria or yeast) or ear mites.
Skin scraping: This test checks for mites, also known as mange (demodex or scabies). The veterinarian gently scrapes the skin to collect a small sample so that deeper cells can be evaluated under a microscope.
Flea comb: A flea comb is used to check for fleas, which often cause itching along the back and base of the tail. Not seeing fleas doesn’t mean they aren’t there in small numbers, as they hide well in the fur. In fact, seeing fleas often doesn’t happen until there is a flea infestation.
Less common tests that your veterinarian may conduct include fungal culture, skin culture, or skin biopsy.
A fungal culture is used if a ringworm infection is suspected. If humans or other pets in the household have skin lesions too, this may increase the suspicion for ringworm.
A skin culture is sometimes needed for bacterial infections to help identify the specific type of bacteria and the appropriate antibiotic to use. This is important when bacterial resistance to antibiotics is suspected and in animals that have been on antibiotics already without resolution of skin infection.
Less common skin diseases that can appear similarly to atopic dermatitis may require a small piece of skin to be collected and sent to a laboratory for testing (skin biopsy). This test may be needed in cases that aren’t responding to treatment for atopic dermatitis.
How to Treat Atopic Dermatitis in Dogs
Treatment of atopic dermatitis in dogs is aimed at controlling the symptoms of excessive itchiness and treating secondary complications like infection.
It is important to recognize that atopic dermatitis is a lifelong condition. While there is no cure, there are many different treatment options that can help to minimize a dog’s symptoms. This can significantly improve the quality of life of dogs with this condition.
Some newer treatments directly target the parts of the immune system (i.e., Apoquel, Cytopoint) and skin barrier (certain topical treatments) that are responsible for atopic dermatitis. As a result, they can be quite effective at managing atopic dermatitis while avoiding some of the long-term side effects that can be seen with other treatments like steroids. Some dogs may undergo additional testing to determine which specific allergens are triggering their allergies. These dogs may be able to undergo immunotherapy (allergy shots), which may reduce symptoms over time. Working closely with a veterinarian or veterinary dermatologist, and often combining multiple treatment types, is the key to successful management of atopic dermatitis.
Medications for Atopic Dermatitis and Other Treatments
Common prescription medications and other treatment options for atopic dermatitis in dogs may include:
Steroids: Steroids such as prednisone can quickly improve itchy, inflamed skin and discomfort, but they are not usually recommended for long-term use due to side effects.
Apoquel: An oral medication that targets/suppresses the immune system directly by blocking substances that cause inflammation and itching.
Cytopoint: An injection that neutralizes a specific protein that causes dogs with atopic dermatitis to become itchy. One injection lasts for 1-2 months.
Allergy-specific immunotherapy: Intradermal skin testing or blood (serum) testing will be done to determine what a dog is specifically allergic to in the environment. The results are used to make a customized allergy medication (injectable or oral). Also called allergy shots, ASIT, or allergy vaccination, this treatment is designed to teach or “desensitize” a dog’s immune system to become less allergic to specific things over time. This is done by exposing them to increasing amounts of these allergens gradually so that their body won’t react to them in the future.
Dermatology diet: Some prescription diets are specially formulated to help manage skin problems and environmental allergies in dogs. For example, Royal Canin Skintopic is a veterinary-exclusive formula that provides itch relief and helps reinforce the skin barrier and promote a strong immune system.
Antihistamines: Over-the-counter antihistamines like Benadryl, Zyrtec, and Claritin may help with mild cases of atopic dermatitis. However, they are usually not effective as the sole treatment. They work better if given before an active flare of atopic dermatitis [6]. NOTE: Some formulations have an added ingredient that is toxic for dogs (i.e., pseudoephedrine in non-drowsy formulations is NOT safe). Only use medications recommended by a veterinarian.
Topicals: Topical treatment can decrease the amount of allergen on the skin, improve the skin barrier, and target any additional inflammation and/or secondary infections directly. This may include bathing with specialized shampoo or using wipes, sprays or mousse for localized treatments.
Supplements: Your veterinarian may recommend giving your dog fish oil supplements, which contain essential fatty acids to support skin and coat health.
Antibiotics or antifungal medications: Used to control secondary infections.
Managing Other Conditions
Your dog’s treatment plan may also include managing conditions that can contribute to excessive itchiness and exacerbate atopic dermatitis.
Skin infections: If your dog has an active skin infection, oral and/or topical therapies may be recommended, depending on the specific type of infection observed. Importantly, each new infection should be checked to determine the best treatment.
Ear infections: Secondary ear infections (otitis externa) can be treated and managed with antibiotics or antifungals for the ear, as well as ear cleaners.
Fleas: Dogs with atopic dermatitis should stay on a year-round, high quality, flea preventative unless otherwise instructed by a veterinarian [6]. Allergies to flea saliva (flea allergy dermatitis) are very common and can exacerbate symptoms of atopic dermatitis. Any flea exposure can be problematic for dogs with allergies. Furthermore, the frequent bathing that many dogs with atopic dermatitis need can decrease the efficacy of some topical flea products.
Some flea and tick preventatives have the added benefit of treating mites like scabies and demodex. This can be useful in helping to rule those out as potential causes for itching and skin lesions.
Food allergies: Not all dogs with atopic dermatitis have additional food allergies or sensitivities. However, if food allergies are suspected, an elimination diet trial may be recommended, especially if a dog has year-round symptoms or additional gastrointestinal symptoms [4].
How to Prevent Atopy in Dogs
Since there is a genetic predisposition to atopic dermatitis, is it best not to breed dogs who are diagnosed with this condition. Once a puppy is born, there is not a way to specifically prevent them from developing atopic dermatitis.
To help avoid flare-ups of atopic dermatitis and its associated symptoms, limit your dog’s exposure to allergens they are known to be allergic to. This may include:
- Removing specific plants from the yard; however, wind can still carry pollen long distances
- Keeping your dog inside after grass has been freshly mowed
- Limiting dust in the house with frequent cleaning and vacuuming, ideally when your dog is not in the room
- Changing air filters and washing bedding more frequently
- Covering dog beds with impermeable covers so they can be cleaned easier
- Using year-round, prescription flea control
- Feeding a prescription novel protein or hydrolyzed diet, if your veterinarian suspects a food allergy or sensitivity
References
- Miller, W. H., Griffin, C. E., Campbell, K. L., Muller, G. H., & Scott, D. W. (2013). Hypersensitivity Disorders. In Muller & Kirk’s Small Animal Dermatology (7th ed., pp. 364–388). essay, Elsevier.
- Griffin CE, DeBoer DJ. The ACVD task force on canine atopic dermatitis (XIV): clinical manifestations of canine atopic dermatitis. Vet Immunol Immunopathol 2001;81:255-269.
- Favrot C, Steffan J, Seewald W, et al. A prospective study on the clinical features of chronic canine atopic dermatitis and its diagnosis. Vet Dermatol 2010; 21:23-31.
- Hensel P, Santoro D, Favrot C, et al. Canine atopic dermatitis: detailed guidelines for diagnosis and allergen identification. BMC Veterinary Research 2015;11:196.
- Hillier A, Griffin CE. The ACVD task force on canine atopic dermatitis (I): incidence and prevalence. Vet Immunol Immunopathol. 2001;81(3–4):147–51.
- Olivry T, DeBoer D, Favrot C, et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Veterinary Research 2015;11:210.
