Dog Skin Allergies and Conditions

Identifying and treating skin allergies and conditions in dogs is essential for their comfort and health. Learn the steps to accurately diagnose these issues, understand the differences among various skin conditions, explore treatment options, and consider the benefits of hypoallergenic diets with guidance from Dr. Judy Morgan, an expert in veterinary medicine.

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 too 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 about its 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 allergic reactions in dogs, several culprits may be to blame—ranging from fleas to skin conditions like atopic dermatitis. According to Dr. Morgan, one of the most common triggers is atopy, or reactions to inhaled allergens. “Diet also plays a major role,” she adds.

Like humans, dogs with atopy react when their immune systems misidentify everyday airborne particles—such as pollen, mold spores, or animal dander—as threats. These reactions typically appear within 30 minutes, and almost always within 12 hours. While atopy is usually seasonal, peaking in spring and summer, dogs in warm, humid climates like Florida or Hawaii may experience symptoms 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

An 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.

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: In this procedure, your dog is sedated and a section of fur is clipped. Then, tiny amounts of around 60 allergens are injected into the skin. It’s considered the gold standard for diagnosing environmental allergies, but results can vary due to weak reactions or subjective interpretation.
• Blood Allergy Testing: This test measures antibody levels to specific allergens. However, reliability varies by lab, and since it tests the blood rather than the affected organ (the skin), results may not always reflect the true cause of symptoms.

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 involves feeding your dog a novel protein and carbohydrate—ingredients they’ve never had before—to help identify sensitivities. Dr. Morgan recommends starting with one protein (like rabbit or fish) and one vegetable (such as kale or butternut squash), avoiding starches. The trial should last at least four weeks.

Dr. Morgan takes a thoughtful approach: “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.

Other Types of Dog Skin Allergies

Not all dog allergies are atopic, although atopic disorders are inherently allergic. Dogs prone to allergies, especially purebreds, may suffer from various types including pest bites and medication reactions.

External Parasites

External parasites are common triggers of allergic reactions in dogs:

• Fleas: Flea allergy dermatitis, caused by flea saliva, can provoke severe reactions and carry diseases like tapeworms and Bartonella.
• Ticks: These blood-sucking parasites attach deeply and are visible when engorged. They are known carriers of diseases and should be removed promptly.
• Lice: Less common but potentially severe, lice can cause itching, pain, and hair loss. Effective removal involves using flea combs and maintaining clean bedding.
• Mites: Responsible for sarcoptic and demodectic mange, mites cause intense itching, red skin, and hair loss.
• Ringworm: A contagious fungus causing circular, scaly patches and hair loss, particularly in young dogs.

Drug Allergies

Reactions to medications, such as penicillin or NSAIDs, can lead to cutaneous adverse drug reactions (CADR), ranging from blisters to severe itching. Diagnosis depends heavily on the pet’s medical history, and treatment varies based on the reaction severity.

This condition occurs from direct contact with irritants or allergens:

• Allergic Dermatitis: Develops over time from repeated exposure to allergens like flea collars, shampoos, or plastics.
• Irritant Dermatitis: Occurs immediately upon contact with harsh substances like detergents or road salt. Prevention involves avoiding exposure to known irritants.

Dry Skin Environmental Factors

Dry, flaky skin can result from over-bathing, low humidity, or overheated environments. Remedies include using moisturizing shampoos, increasing water intake, and using humidifiers to adjust the humidity level at home.

Other Non-Allergy Based Skin Conditions in Dogs 

Many skin conditions can resemble allergies but stem from entirely different causes. Only your veterinarian can determine the true source of your dog’s discomfort. Here are a few examples:

• Hormone Responsive Dermatosis and Alopecia in Dogs: Skin inflammation (dermatosis) and hair loss (alopecia) may result from imbalances in reproductive hormones. If diagnostic tests suggest a hormone-related issue, your vet may recommend hormone therapy to restore balance—either increasing or decreasing hormone levels as needed. In some cases, neutering or spaying may be enough to resolve these issues. If adverse reactions occur during hormone therapy (e.g., estrogen), treatment will be adjusted or discontinued. Improvement of skin and coat health following hormone correction confirms the diagnosis. Your vet may also prescribe medicated shampoos and topical treatments to manage dandruff, itching, or secondary bacterial infections.
• Bacterial Infections: Pyoderma is a bacterial skin infection that causes redness, rashes, itching, crusting, pustules, and hair loss. It often occurs when your dog’s natural skin defenses are compromised, allowing bacteria—and sometimes yeast or fungi—to take hold. A range of underlying factors can weaken the skin’s defenses, including allergies, irritants, and autoimmune diseases. Because pyoderma often has multiple causes, treatment typically requires a comprehensive approach guided by your veterinarian.

Dog Skin Allergies

Atopic dermatitis can be managed in several ways. While limiting your dog’s exposure to allergens is ideal, it’s not always practical—after all, moving may not be an option! Here are some common therapies for specific allergy triggers:

• Flea Control: Use a combination of methods such as topical treatments, oral medications, and flea-specific shampoos—especially if your pet spends a lot of time outdoors.
• Plant Allergens: Avoid irritants like Euphorbia and the Gas Plant, which can trigger contact or atopic allergies. For more information, see Allergy-Free Gardening.
• Immunotherapy: Also known as hyposensitization, this involves allergen-based injections to help your dog build tolerance and reduce sensitivity over time.
• Anti-Inflammatory Medications: Steroids and newer non-steroidal drugs can help manage symptoms. Antihistamines and fatty acid supplements may also be effective for milder cases.
• Topical Therapy: Bathe your dog regularly with medicated shampoos and conditioners to remove allergens and soothe the skin. Use lukewarm water to help reduce itching.
• Antibacterial and Antifungal Treatment: Treat recurring bacterial or yeast infections with appropriate medications or medicated shampoos designed to target these issues.

Many skin allergies in dogs take time to resolve. Be patient, follow your veterinarian’s guidance, and support healing with a healthy, immune-boosting diet.

Key Treatment for Skin Allergies

Dr. Morgan offers key guidance on choosing diets for dogs with skin allergies, recommending hypoallergenic or novel protein options. She cautions against hydrolyzed protein diets, noting, “I do not like hydrolyzed protein diets, as I find them effective less than 50% of the time. Many assume they work well, but that’s often because they’re paired with steroids, antihistamines, or other immunosuppressants like cyclosporine or Apoquel—so the food itself may not be doing the heavy lifting.”

For faster, more reliable relief, she recommends simplified home-cooked or raw diets using novel proteins. “I’ve never found a kibble that works well for this—they contain too many ingredients,” she explains. Dr. Morgan also points to studies showing contamination in commercial diets: “Four studies found that 80% of ‘limited ingredient’ kibbles—both prescription and over-the-counter—contained unlisted proteins. That makes them nearly impossible to use as an accurate food trial.”

Implementing Hypoallergenic Diets

Following Dr. Morgan's expert advice, here are practical steps for implementing hypoallergenic dog diets:

• Avoid Common Food Allergens: Carefully read labels to ensure the diet does not contain typical allergens. Adjust the diet by periodically changing the proteins to see what works best for your dog.
• No Chemicals or Preservatives: Opt for diets that prioritize high-quality, natural ingredients without industrial additives.
• Strengthen the Immune System: A diet rich in natural nutrients can bolster your dog’s immune defenses, helping to ward off allergies and other conditions.
• Natural/Ancestral Dietary Approaches: Consider diets that align with dogs' historical dietary patterns—primarily those high in meat and balanced fats, similar to what their ancestors would have eaten.
• Single Meat Source: Simplify your dog’s diet by focusing on a single source of meat protein to help identify and eliminate allergens effectively.

Dr. Morgan’s experience and research underscore the importance of a carefully chosen diet to manage and alleviate the symptoms of allergies in dogs. By adhering to these guidelines and considering the role of diet in overall health, pet owners can significantly improve their dogs' quality of life.

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.

Conclusion

In conclusion, managing dog allergies, whether they originate from food, environmental triggers, or seasonal change, requires consistent attention and a clear understanding of potential causes. Keeping a close eye on symptoms such as persistent scratching, skin irritation, or recurring infections can help guide the right course of action. Early identification and treatment of food sensitivities and skin conditions are essential in minimizing discomfort and preventing more serious complications. Consulting with your veterinarian ensures that your dog receives accurate diagnoses and personalized care based on their specific needs. Every dog is different, and their overall health, environment, and diet should be thoughtfully considered when building an allergy management plan. With the right knowledge and support, you can help your dog lead a comfortable, happy, and healthy life.