Dog Skin Allergies and Conditions

Inside This Article

• What Causes Dog Skin Allergies?
• Is it an Allergy or Something Else?
• Difference Between Food Intolerance and Food Allergies
• Treatments For Dog Skin Allergies

Is your dog’s itchy, uncomfortable, or unsightly skin condition driving them — and you — up the wall? Getting to the root cause is the key to beginning the healing process. Find out how to diagnose skin allergies and conditions, how they differ, how to treat them, and about hypoallergenic dietary solutions from an expert in the field, Dr. Judy Morgan.

Dog Skin Allergies and Their Causes

Pruritus is the medical term for severe itching of the skin. It’s the generic name for the wide variety of dog skin disorders that cause your pet to lick, scratch, or bite to try to stop the itch. A number of conditions, from atopic dermatitis to hormone-related issues, can prompt these conditions. To sort them out, we looked to a vet with years of experience.

Dr. Judy Morgan is an author, speaker, and holistic veterinarian. Based in New Jersey, Dr. Morgan currently operates two veterinary hospitals, is an active speaker and blogs and writes daily. She has published three books on holistic pet care and feeding, and her social media sites reach millions of pet owners worldwide. She is Chief Veterinary Medical Officer for Monkey’s House Senior Dog Hospice and works with rescue groups for homeless dogs.

Your dog’s skin is in perfect condition when it’s soft and smooth and not flaky, red, bumpy, or oozing. It shouldn’t be too oily or dry to your touch, and there shouldn’t be any bald spots. But you’ll usually know before you even check that something’s amiss because your dog can’t stop worrying his or her skin.

Before you begin trying to relieve your dog’s discomfort, it’s important to understand the different forms of skin allergies and conditions so you and your vet can take the best course of action.

Atopic Dermatitis: What Is It, and How Does It Develop?

When it comes to causing allergic reactions in dogs, a number of factors can be culprits — from fleas to atopic dermatitis. When it comes to typical triggers of dogs’ skin problems, Dr. Morgan notes that one common cause is “atopy or inhaled allergens.” However, she notes, “Diet also plays a major role.”

Like people, canines manifest atopic allergic symptoms when their immune systems begin to recognize certain everyday inhaled substances as dangerous. Atopy reactions usually occur within 30 minutes of contact with the allergen, and always within 12 hours. Atopy is about reacting to inhaled particles, such as airborne pollens from plants and grasses, weed and trees, mold spores, and, in some cases, animal dander. Atopy is usually seasonal, with the worst symptoms occurring in the spring and summer. However, if you live in warm, humid areas like Florida or Hawaii, the problem can be year-round.

Think skin allergies in dogs are pretty uncommon? That’s unfortunately not the case. It’s hard to see your dog suffer, and the secondary manifestations of skin lesions, infections, and hair loss can be alarming. In addition, the constant scratching can be a source of irritation for pet owners. In fact, skin allergies are the most common reason people take their canine companions to the vet for consultations, according to Nationwide Pet Insurance. If susceptible, dogs usually show allergy symptoms as early as 3 months and up until around age 6. Atopic dermatitis can be mild at younger ages, so it may not become apparent or a real problem until your dog is 3 years old. Symptoms are usually skin related — itching, scratching, and rashes — but depending on the trigger, they can also manifest as “hay fever” symptoms like watery eyes and sneezing.

Preparing For Your Vet Visit

Accurate diagnosis of an allergy in your dog requires a comprehensive exam by your vet. To make the most of your visit, take some time to prepare and have answers for the questions your vet will likely ask:

Your veterinarian should be able to make a diagnosis more easily using your answers. But the appearance of your dog’s skin is where the exam will begin.

What Dog Skin Allergies Look Like

Not everything that manifests on your dog’s skin is allergy-related. Itchy skin can also be caused by dandruff, fleas, parasites, mites, plain old dry skin — or no reason at all. Some dogs scratch themselves “just because.” But consider these signs to watch for:

• Inflammation
• Rashes
• Dry or flaky skin
• Redness or discoloration
• Lesions or scabs
• Scaly patches
• Bald patches
• Swelling or lumps
• Hot spots (areas where itching is particularly intense)

Even if your canine companion has some of these symptoms, it may not be an allergy you’re looking at. Some skin conditions mimic allergies.

Diagnostic Testing: Is It an Allergy — Or Something Else?

Here’s an example of a condition that mimics allergies: a yeast infection found on the skin and ears of dogs caused by Malassezia pachydermatitis. Though it’s completely normal for canines to have this type of yeast, an overgrowth can cause dermatitis or skin inflammation. The reasons for the condition aren’t known. The symptoms look like typical atopic allergies, but the cause and treatment is very different.

So how does your veterinarian make an exact diagnosis of the cause of your dog’s torment? There are three common processes:

• Intradermal Allergy Testing: Your dog will be sedated for this procedure. After hair has been clipped on one side of your pet’s body, your vet will give minute injections of allergens, usually 60, on one side of your pet’s body. While considered the state-of-the-art in diagnosis for pet allergies, it can be less than 100 percent reliable both when reactions are not strong and since there is some subjective interpretation involved.
• Blood Allergy Testing: This test attempts to measure antibody levels your pet has formed against particular allergens. There is some debate about blood testing reliability since the affected organ is not what’s being tested for a reaction. Depending on the lab used, results may not agree.

Neither intradermal or blood allergy testing can determine food allergies. “People need to understand that the only way to really know for sure if there is an allergy is to feed something and see how the pet reacts,” Dr. Morgan notes. The way to do that is a food trial or elimination diet.

• Elimination Diets and Food Trials: This entails feeding your dog novel sources — a protein and carbohydrate that your pet has never eaten before — to see which foods cause an allergic reaction. It can help identify food sensitivities.

Dr. Morgan takes a thoughtful approach: “I usually start with a novel protein like rabbit or fish, something the pet has not eaten in the past,” she explains. “I do not worry about having a balanced diet while going through the trial. I generally pick one protein source and one vegetable source (like kale or butternut squash), eliminating starches, and feed that for 4 weeks, minimum. If the pet is responding well, then I start adding in one new thing per week, like eggs or turkey, to see if the pet reacts. Once the system has been ‘cleaned,’ reactions will occur pretty quickly, usually within 24 to 48 hours.”

Based on one, two, or all of these diagnostic processes, you’ll be closer to knowing what you’re dealing with and how to treat it.

Beyond Atopic Dermatitis: Other Types of Dog Skin Allergies

Not all allergies are atopic, although all atopic disorders are allergies. For example, pest bites and food allergies are non-atopic allergic disorders. Dogs that are allergy-prone tend to have more than one type, and purebred dogs are more often affected by allergies than mixed-breed companions.

The causes in addition to atopic disorders for skin allergies fall into multiple categories:

1. External Parasites: Dog skin parasites range from mild to severe and each type can cause a different reaction in your dog. In general, it’s good to get the advice of your vet on the best way to control them. Here are some of the pests that can bedevil your dog:

Fleas: Extremely common, flea allergy dermatitis is caused by the flea’s saliva, and it only takes a few bites of this blood-sucking parasite to set the problem off. Controlling them should be a priority because fleas carry tapeworms, Bartonella, and other diseases.

Ticks: Ticks deeply attach to the skin to extract blood, eventually falling off to lay their eggs. Dogs will often show no symptoms, but you can easily see ticks because they become engorged and protrude from the skin. As disease carriers, they should be removed as soon as possible. The Centers for Disease Control (CDC) offers advice on the best way to remove a tick.

Lice: Lice are less common on dogs than ticks and fleas and may be difficult to find since you’ll need to look for the tiny eggs attached to your dog’s hair follicles. Lice don’t only cause itching, pain, and hair loss, but they can lead to more serious health issues, so they should be eradicated as soon as possible. Use flea combs to remove lice, disinfect the comb, and clean pet bedding in hot water. Most flea shampoos also remove lice. Seek veterinary advice for persistent cases.

Mites: These tiny parasites cause two types of mange. The most easily transmitted to both dogs and people, sarcoptic mange is also known as canine scabies. A dog’s ears, face, and legs are most commonly affected, with symptoms of red skin, intense itching, sores, and hair loss. The second type isn’t contagious between dogs or humans, but demodectic mange can cause bald spots, scabbing, and sores.

Ringworm: The name of this fungus comes from the circular patches it causes on any site of your pet’s body — or yours since it’s highly contagious between both dogs and humans. You may see scaly patches, inflammation, and hair loss around the area of the circular lesions. Dogs under a year old are most susceptible.

2. Drug Allergies: Orally, topically, or intravenously administered drugs can prompt a cutaneous adverse drug reaction (CADR). Symptoms can range from blisters to hives, and dogs may experience acute itching that results in self-mutilation. It can be difficult to diagnose a drug reaction because the symptoms can start one to three weeks after first administration of a drug, and reactions can happen even three weeks after the therapy has ended.

The most common medications causing skin reactions to drugs include penicillin vaccines, antimicrobials, sulfonamides, topical drugs, and NSAIDs. Your pet’s medical history will be an important part of the diagnosis, and treatment will depend on the severity of your pet’s skin condition. Resolving a cutaneous adverse drug reaction is never an instant procedure; the veterinarian may decide to stop or replace the prescription, but all of this must be done under careful observation. Be prepared for frequent follow-up appointments and communication in order to see if the cease in medication is solving the reaction. In mild cases, simply stopping the drug can reverse the adverse effects.

3. Contact Dermatitis: There are two types of contact dermatitis. In both cases, the dog has direct physical contact and a reaction to an irritating substance. Allergic dermatitis happens when a dog becomes hypersensitive to substances in their environment after repeated physical contact and skin sensitization. Skin sensitization can take anywhere from six months to two years to develop. Various substances can cause allergic contact dermatitis, including flea collars/flea powders, topical antibiotics, some metals, soaps/shampoos, carpet deodorizers, insecticides, and plastic.

Irritant contact dermatitis occurs the first time that your pet makes contact with an extremely irritating substance. Common chemicals and substances that cause irritant contact dermatitis include road salt, detergents, acids and alkalis, and petroleum byproducts. There is no cure for contact dermatitis. The best way to treat and prevent the disease is to prevent exposure.

4. Dry Skin/Low Humidity: Irritated, dry skin can have multiple causes, including over-bathing or bathing with too much soap and not rinsing thoroughly. Another common cause is overheating the home in winter months, or low humidity levels due to the climate you and your pet live in. This is easy to remedy once you know the reason by making changes in your environment by buying a humidifier, using specially formulated moisturizing shampoo and conditioner if you live in a dry area, and encouraging more water consumption.

Other Non-Allergy Based Skin Conditions in Dogs 

Dogs may experience a number of other skin problems that look like allergies. Only your doctor will be able to tell you if they are the reason for your dog’s discomfort. Consider these examples:

• Hormone Responsive Dermatosis and Alopecia in Dogs: Dermatosis (diseases affecting the skin that cause inflammation and itching) and alopecia (hair loss) can be related to an imbalance of reproductive hormones. Various reasons could cause your dog to have these types of reactions, but if tests and indications point to reproductive hormone imbalance, your vet will try supplemental therapy to either raise or lower hormones to achieve a normal level. If your dog is on estrogen therapy, and the results are adverse to the health of your dog, your veterinarian will discontinue it. Dermatosis and alopecia are confirmed when the conditions resolve based on hormone therapy. Another approach is neutering or spaying, which may be sufficient to resolve the skin disorders. Your veterinarian will prescribe prescription shampoo for dandruff and topical medicines for the treatment or prevention of bacterial skin infections and itching.
• Bacterial Infections: Pyoderma is the medical term for bacterial infection of the skin. It can cause redness and rashes, itchiness, crusts, pustules, and even hair loss at the infection site. Once the natural defenses of your dog’s skin break down, opportunistic bacteria proliferate. Yeast and fungal organisms can also establish their own infections when the skin’s defenses have broken down. Any interruption to the immune system’s ability can lead to pyoderma, including damage to the skin because of different kinds of allergies, irritants, and/or autoimmune disease. Treatment is usually multi-faceted because of the nature of the disease and needs to be directed by your vet.

Many disorders are based on lowered immunity, like pyoderma. If your dog suffers from any kind of illness, it’s always good to assess what and how you’re feeding your dog.

The Difference Between Food Intolerance and Dog Food Allergies

Food can be a major cause of skin issues, according to Dr. Morgan. “Grains tend to be incriminated a lot, however, there can be many triggers,” she says. “Some dogs are allergic to protein sources like chicken or beef or fish. I have many patients that suffer from yeast overgrowth when they are fed diets high in carbohydrates of any type. Most people blame grains, but peas, lentils, potatoes, and other starches can be just as bad.”

“Food allergies are true allergies with an immune system reaction that causes the characteristic symptoms of itching, skin disease, facial swelling, or swelling of the ears,” explains Dr. Morgan. “Food intolerances usually result in vomiting or diarrhea and don’t create a typical allergic response.”

Food intolerances in pets are similar to the digestive problems of people who get an upset stomach or diarrhea because of lactose intolerance. The best way to get rid of the problem: For people and their pets, identify the food causing the problem and eliminate it from the daily diet.

Allergies and intolerances for your dog can be identified by the method described by Dr. Morgan in the diagnosis section of this article.

Common Food Allergens

Like people, dogs can be allergic to just about any food, but the grains and meats that are more likely to cause problems:

• Beef
• Pork
• Fish
• Rabbit
• Chicken
• Lamb
• Egg
• Corn
• Soy
• Wheat
• Dairy

It may seem overwhelming to care for a dog with food allergies. But it’s much simpler today than it was in the past. Many more wholesome foods are available, featuring a wide variety of protein and grains to meet your canine companion’s health needs. With a little care and education, you can keep your dog safe, happy, healthy, and well fed. But where do you find the right kind of food?

The Trouble With Commercial Dog Food

Allergies are the result of an immune system overreaction, which only develops after repeated exposure to potential allergens. If your dog has skin allergies or skin conditions that make life miserable, there are a whole host of reasons to take a close look at the content of commercial dog food and reconsider what you’re feeding. Here are some of them:

• Common Allergens are Common Ingredients: Very common allergenic ingredients contained in many popular commercial pet foods — such as corn, wheat, rice, soy, eggs, milk, yeast, potato, and beets — are often potential culprits. Many pets react to certain animal proteins as well.
• Lack of Variety: Many people who have observed the rise in the dogs’ health issues connect them to pet food brand loyalty. Feeding your dog the same food day in and day out for years can increase the likelihood of a reaction to food ingredients.
• Fillers: In addition, most commercial pet food contains fillers like potatoes and other fibers and starches to help make food more economical to a product by reducing the amount of meat in the food. However, these fillers aren’t biologically appropriate for dogs. Over time, they create stress on the immune system, which in turn can develop a hypersensitivity and resulting allergic response to them.
• Additives: Emulsifiers, flavor enhancers, dyes, and preservatives, and even the hormones and chemicals passed up the food chain from meat can trigger food intolerances. Food intolerances can escalate to systemic allergic reactions.
• Poor Quality: Feeding rendered, low-quality sources of protein — for example, hooves, feathers, or beaks — has the potential to initiate an allergic reaction in your pet.

To learn more about choosing the right diet for your dog, bone up on how to compare different types of dog food.

Treatments for the Most Common Factors in Dog Skin Allergies and Conditions

Now that you know the basics of diagnosis, types, and causes of skin allergies and conditions, let’s consider treatments for the main problem areas for dog skin allergies and food-related conditions:

Key Environmental Allergy Treatments

Atopic dermatitis can be treated in many different ways. Limiting your dog’s exposure to his allergens is ideal, but may not be feasible — after all, moving may not be possible! Here are some therapies for specific ailments:

• Flea Control: For the No. 1 dog skin irritant, you can find lots of different flea-killing options. Since they are all useful for limited amounts of time, they need to be repeated as indicated. Many flea-control products are applied topically where your dog is unable to lick them off, such as behind the head on the neck. Products given orally may be more practical for you and your dog. Specially formulated flea-killing shampoos can also be helpful if the infestation is acute or for puppies, but you’ll still want to continue with either topical or oral medication. If your pet spends a great deal of time outdoors, you’ll need to be extra-diligent. And if your house becomes infested, you’ll need to take steps to treat your home and repeat the process to keep the pests away.
• Avoid Certain Plants: Some plants can cause contact dermatitis in dogs because of their sap (like Euphorbia) or atopic allergies due to their pollen (like the Gas Plant). Beware of how your garden grows! For a list of plants to avoid to safeguard your dog, check out Allergy-Free Gardening.
• Immunotherapy (Hyposensitization): To activate “tolerance,” injections made from allergens that your pet is sensitive to can be administered in a series. The therapy will make your dog less sensitive to them when they are re-encountered in your home or outside. Injections are usually given at home, but pills or drops are available if your dog can’t tolerate shots or if you dislike giving injections.
• Anti-Inflammatory Medications: Steroids and some new non-steroidal drugs can help manage dog allergies. Oral medications used in combination can be safer than a single drug at a higher dose. Some dogs benefit from a trial with different drugs to find one that works best. Antihistamines and fatty acid supplements can be helpfully used with other treatments or for dogs that are less severely affected.
• Topical Therapy: Medicated shampoos and conditioners can provide relief. Bathing removes allergens that adhere to the skin’s surface, and the medicated ingredients also help to reduce itching and control secondary infections. Using lukewarm water for these medicated baths also helps cool the skin to further reduce itching.
• Antibacterial and Antifungal Medications: Because dogs with atopic dermatitis are prone to recurrent bacterial and yeast infections of the skin and ears, your veterinarian may need to address these infections in addition to treating atopic dermatitis. Medications used might include courses of antibiotics and/or antifungals. Your veterinarian may also prescribe topical therapy with antibacterial and antifungal shampoos to resolve and prevent bacterial and yeast infections.

Many dog skin allergies and conditions take a long time to heal. Be patient, follow the doctor’s orders, and take steps to improve your dog’s diet to support immunity and overall good health. 

Key Treatment for Food Allergies

Dr. Morgan offers valuable advice on choosing a diet suitable for dogs with skin allergies and other skin conditions. She suggests hypoallergenic diets or novel protein diets. “I do not like the hydrolyzed protein diets, as I find them to be effective less than 50 percent of the time,” she reports. “Many people think they have higher effectiveness, but they are commonly using them along with steroids, antihistamines, or other immunosuppressive drugs (cyclosporine, Apoquel), so the food probably is not as effective as they might believe.”

She goes on to say that there may be a quicker way to get your dog’s skin — and your frazzled nerves — on a more even keel. “For people wanting a faster route, I point them toward home-cooked or raw diets with minimal ingredients using novel protein. I have never been able to find a kibble product that works well for this,” Dr. Morgan says. “They simply have too many ingredients. There were four studies done a few years ago that showed 80 percent of ‘limited ingredient’ kibbles (prescription and over-the-counter) were contaminated with proteins that were not listed on the label. Therefore, it is almost impossible to use this as a test.”

Experience and research inform Dr. Morgan’s approach. “Many pets will respond very well to raw diets, even those made by commercial companies,” she says. The reason for this is simple, in her estimation. “I think this is because those diets are extremely low in carbohydrates. The carbohydrates break down into sugars, which support yeast overgrowth. Carbohydrates change the pH in the gut, supporting more of the ‘bad’ microflora than the ‘good’ microflora. It also changes the pH of the skin, allowing yeast overgrowth. Diets high in meat create a more acidic environment.”

To sum up, here are things to look into for hypoallergenic dog diets:

1. Doesn’t Contain Common Food Allergens: Read labels carefully. Once you determine your dog’s sensitivities, you can make a selection based on what works best and vary between the best ingredients by changing the proteins periodically.
2. No Chemicals or Preservatives: Look for high-quality ingredients. Industrial additives aren’t good for dogs or humans since they are not natural to mammal biochemistry.
3. Immune System Strengthening: Better nutrition will strengthen natural protection and biological systems, which helps ward off allergies and other conditions.
4. Natural/Ancestral Approach: Canines successfully evolved with a scavenging and hunting lifestyle, consuming foods that are nothing like the highly processed kibble fed to many dogs today. Recent nutritional science increasingly supports diets based on what nature intended — fresh foods that are high in protein and provide fats that are balanced fats — as the healthiest approach to feeding most dogs. Learn more about the many benefits of the Ancestral Diet.
5. A Single Meat Source: Having one meat protein source makes it easier to eliminate what’s causing skin problems in your dog and feeding what will support her good health.

If you want to avoid skin and other health worries, offering your dog meals that contain whole foods with nutrients in their natural state simply makes sense. Want to learn more about how food can ease allergies? Read more about hypoallergenic dog food and dog food to ease skin allergies on Darwin’s Natural Pet Products blog.

Darwin’s Can Help You Stop the Itch and Other Dog Skin Issues

Robust and natural nutrition can build immunity, support skin health, and relieve your dog’s suffering. If you’re looking for guidance on the best hypoallergenic food for your special friend, get a free menu consultation from a Darwin’s expert by calling 877-738-6325 or emailing us with your questions. When it comes to allergies and intolerances, the right food can make all the difference.