Dog Allergies: Symptoms, Testing, and Treatment

Does your dog scratch, lick, chew, or rub their skin more than usual? Do they have recurring ear problems, inflamed skin, vomiting, or diarrhea? Allergies may be one possible cause. As a loving pet parent, few things are worse than watching your dog experience pain and discomfort, and unfortunately, suspected food and skin allergies in dogs have been on the rise for over a decade.

Dog allergies cannot usually be cured, but they can often be managed. Recognizing the signs early and working with your veterinarian can help your dog feel more comfortable.

What Are The Different Types of Dog Allergies?

Dogs experience allergies when their immune system overreacts to a typically harmless substance, such as pollen, plants, an ingredient in their food, or insect bites. The substance is classified as a foreign invader (also known as an allergen), and the immune system sends antibodies to attack, causing distressing symptoms.

Allergies can affect any dog regardless of age, breed, or sex, and symptoms may appear seasonally or year-round depending on the trigger. To understand what may be causing your furry friend’s allergic reactions, let’s take a closer look at the different types of allergic skin diseases in dogs.

Environmental Allergies in Dogs

Environmental-based allergies are triggered by things in your dog’s everyday environment that can be difficult or nearly impossible to avoid. They are typically at their worst in the spring, summer, and fall months when plants and trees pollinate, leading to seasonal allergies.

Common environmental allergens include:

• Dust
• Grass
• Pollen
• Weeds
• Dust mites
• Plants and trees
• Mold and mildew

Food Allergies in Dogs

Dogs may experience intolerances, sensitivities, and allergies to ingredients in their food and treats. The immune system typically attacks a part of the food, such as the proteins, carbohydrates, or additives, according to veterinary dermatologist Dr. Jangi Bajwa. Food allergy symptoms may be similar to environmental-based allergies, but typically also involve digestive upset.

Common food allergens include:

• Soy
• Rice
• Beef
• Pork
• Dairy
• Eggs
• Lamb
• Wheat
• Chicken

Flea Allergy Dermatitis in Dogs

Flea allergy dermatitis is a leading cause of dog allergies. Fleas and other biting insects are common across the United States and thrive in most climates year-round, latching onto and feeding on pets for an easy meal. When fleas and insects bite, they leave behind a small amount of saliva on the skin that can cause allergic reactions in sensitive dogs. There doesn’t have to be an infestation for dogs to experience an allergic reaction—one bite is all it takes.

Dog Allergy Symptoms to Watch For

Have you ever seen your dog excessively itching or scratching and wondered, “Is my dog having an allergic reaction?” Or maybe you’ve noticed symptoms that may align with allergies but aren’t quite sure that’s what’s causing their discomfort.
“Just like in people, allergic reactions in pets can be sudden and dramatic, and also cause discomfort and frustration,” explained Julie Buzby, DVM, CAVCA, CVA. “Being familiar with the signs and symptoms could help spare your pet from needless suffering. Generally, the earlier a pet parent recognizes the symptoms and can get their pet to the veterinarian, the better the outcome.”

Pet parents often notice subtle signs, such as increased scratching, licking, or diarrhea, before realizing allergies may be at play. However, it’s important to recognize concerning signs that your pet may be struggling with allergies and seek veterinary care to avoid complications, such as infections and inflammation.

External allergens, such as environmental-based triggers and fleas, typically present clinical symptoms, such as:

• Hair loss
• Hot spots
• Irritated eyes
• Head shaking
• Red and inflamed skin
• Recurring skin infections
• Itching, scratching, biting, and/or rubbing at the skin (particularly on the face, paws, belly, limbs, ears, and rear end)

Clinical signs of food allergies may include:

• Weight loss
• Hyperactivity
• Lack of energy
• Increased dandruff
• Digestive upset, such as vomiting, diarrhea, soft stool, or gas
• Itching, scratching, biting, and/or rubbing the skin (particularly on the face, paws, belly, limbs, ears, and rear end)

“Should you suspect that your pet is suffering from allergies or having an allergic reaction, call your veterinarian,” Dr. Buzby advised.

If your pet exhibits symptoms that may align with dog allergies, seek advice from your AAHA-accredited veterinarian. Early intervention is key to preventing complications and helping your dog feel better.

How Do Veterinarians Test for Dog Allergies?

Managing dog allergies starts with identifying the allergen(s). Your veterinarian will review your dog’s history and dermatologic database to determine if there have been changes to routine or lifestyle, according to the 2023 AAHA Management of Allergic Skin Diseases Guidelines. Diagnostics may also include skin scrapes, fungal cultures, blood tests, or fecal analysis to rule out other non-allergy health concerns.

If food allergies are suspected, your veterinarian may recommend a food elimination trial. This involves feeding a strict, limited diet over the course of a few weeks or months. If the symptoms resolve during the trial, a food challenge is implemented to reintroduce the dog’s old food and monitor for symptoms. If signs return during the challenge, a food allergy is confirmed.

If food allergies, flea allergies, and non-allergic skin disease are ruled out, your veterinarian may use intradermal skin testing and/or blood testing known as radioallergosorbent (RAST) testing to determine what environmental-based allergen is triggering allergic reactions in your dog. RAST testing only requires a single blood sample; no sedation or anesthesia is necessary. The results are then used to guide the formulation of hyposensitization therapy and canine immunotherapy.

What Treatments Are Available for Dog Allergies?

Although dog allergies can’t be cured, they can be managed with proper treatment tailored for your dog’s unique needs.

“When I graduated from veterinary school many years ago, we didn’t have the greatest options for diagnosing and treating pet allergies,” said Dr. Buzby. “Today, there are fantastic, targeted treatments available to bring your pet relief and you peace of mind. Your trusted veterinarian is always your best resource for diagnosing the issue and providing the help your pet needs.”

Here are a few treatments your veterinarian may consider if allergies are determined:

Environmental Allergy Treatment for Dogs

If testing confirms environmental-based allergies, your veterinarian may recommend allergy shots known as immunotherapy. Custom-formulated injections administered throughout the lifetime of a dog retrain the immune system to not overreact by slowly exposing the dog to small amounts of an allergen and increasing the exposure over time until the body grows tolerant of it. According to Purdue University’s College of Veterinary Medicine, 60%-80% of pets improve with immunotherapy injections.

Other common dog allergies skin treatment include:

• Injectable monoclonal antibodies to block itch
• Oral medications that can reduce allergic inflammation and itch
• Oral or topical steroids
• Omega Fatty acid supplements
• Specialized shampoos, creams, and ointments

Food Allergy Treatment for Dogs

The most effective approach to mitigating food allergies is careful avoidance of the offending ingredient. Prescription diets, such as veterinary hydrolyzed or novel protein diets and home-prepared novel protein diets as formulated by a veterinary nutritionist, may be recommended. Dog foods sold in retail stores that claim to be “limited-ingredient” or do not list your dog’s food allergen as an ingredient should be avoided, as they are not manufactured with the same careful adherence to health and safety protocols as prescription diets and may risk cross-contamination.

Flea/Insect Allergy Treatment for Dogs

If your dog is diagnosed with a flea or insect allergy, the best strategy is to use veterinarian-prescribed flea and tick preventative medication year-round. Although even with routine use of preventatives, there is still a risk of bites. That’s why your veterinarian may also recommend keeping dog itch medication on hand for immediate relief.

How Can I Manage Dog Allergy Flare-Ups?

You can support your dog in preventing allergic flare-ups, managing irritation, and avoiding allergens by:

• Using an air purifier to reduce airborne allergens.
• Limiting time outdoors during peak pollen seasons.
• Keeping your dog on flea prevention all year round to prevent flea allergy dermatitis.
• Adding omega-3 fatty acid supplements to support skin and coat health.
• Bathing your dog using hypoallergenic or moisturizing dog shampoos (avoid over-bathing, which can dry out the skin and coat).
• Wiping your dog’s paws, skin, and coat with a wet rag or fragrance-free grooming wipes after walks and time outside.

Your dog is counting on you to be their best advocate. By recognizing the signs of dog allergies and working closely with your AAHA-accredited veterinarian, you can create a treatment plan that will bring your dog some relief and have their tail wagging again.