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14 Dog Allergy Symptoms You Shouldn’t Ignore

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  • Dog allergies are very common but also very treatable.
  • Flea allergies, environmental allergies, and food allergies are the three main dog allergy categories.
  • Dog allergy symptoms include itchy skin (most common), rashes, excessive licking, sneezing, and vomiting, among many others.
  • Dog allergy treatment focuses on managing the allergic response, as opposed to eliminating the allergy itself.
  • There's plenty you can do at home to help manage your dog's allergies as well.

Dog allergies are, unfortunately, very common in our furry friends. Allergies in dogs, like in people, occur when the immune system overreacts to certain substances, ranging from environmental allergens, like dust or pollen, to ingredients in your dog’s food. And that can leave our canine companions suffering a wide range of uncomfortable dog allergy symptoms. 

Fortunately, veterinary medicine has come a long way in the past decade, providing several highly effective treatments for alleviating allergy symptoms in dogs. While that’s great news for pups and pet parents, it’s still important to know what the symptoms of dog allergies are, since they play an important part in recognizing, diagnosing, and treating dog allergies correctly. 

Wondering if your pooch has allergies? Here’s a helpful overview of dog allergy symptoms to watch out for, along with guidance about how to help allergic dogs get relief.

Understanding Dog Allergies

Dog allergies are generally categorized into three types: flea allergy, environmental allergy, and food allergy. However, it is worth noting that many dogs with allergies can have more than one type, and the allergy symptoms associated with each type tend to overlap. 

That means you can’t necessarily pinpoint whether or not your dog has allergies (or what kind) just by observing a few symptoms. But keeping track of those symptoms can help you provide your veterinarian with a clearer picture of what’s going on with your dog’s health.

Common Dog Allergy Symptoms

The most prevalent dog allergy symptom is itchy skin, which can be triggered by all three allergy types — flea, environmental, and food. 

But most dogs are prone to scratching from time to time, for a variety of reasons. So how can a concerned pet parent tell the difference between an inconsequential itch and itchy skin due to allergies? 

Intensity and persistence are two important clues. Dogs with allergies are often so itchy, their efforts to relieve the itch can lead to secondary symptoms, such as hair loss and skin infections.

The other indicator is the presence of additional dog allergy symptoms. Here’s a comprehensive list of dog allergy symptoms to keep in mind if you think your dog might have allergies. 

Dog allergy symptoms relating to skin:

  • Red, itchy, inflamed skin
  • Visible rashes or hives
  • Excessive licking, scratching, or chewing of skin or paws
  • Poor coat condition due to shedding, hair loss, or hot spots
  • Itchy ears
  • Unpleasant odor
  • Skin infections

Other dog allergy symptoms: 

None of these symptoms, on its own, is a surefire sign your dog has allergies. But if your dog is showing several symptoms, it’s worth raising the issue with your veterinarian to see if further testing or diagnosis is warranted. 

Diagnosing Allergies in Dogs

Veterinarians diagnose dogs with allergies all the time. According to Nationwide Pet Health Insurance, over the past decade, members have filed more claims for the treatment of skin allergies in dogs than any other health condition.

However, determining what, exactly, your dog is allergic to may take some detective work. And that usually starts with the skin. 

All three types of allergies can cause what veterinarians call allergic dermatitis (inflammation of the skin), which brings with it reddening, swelling, and itching. Often, the location of the most intense scratching and chewing may indicate what type of allergy could be causing the reaction.

  • Dogs with flea allergies tend to chew relentlessly chew at the back of their hind legs and the base of their tail.
  • Dogs with food allergies are more likely to lick and chew at their feet. 
  • Dogs with environmental allergies often scratch their ears and experience general itchiness, although there can be variations. 

Again, these distinctions are not absolute, but they may provide clues to inform your dog’s diagnosis. Here are some additional dog allergy considerations.

Diagnosing Flea Allergies in Dogs

In addition to the itch response above, the presence of fleas, flea bites, or flea dirt on dogs who have scratched or chewed themselves raw is a strong indication of flea bite allergy. For dogs who are severely allergic to fleas, even one bite is enough to cause them to chew all the hair off their legs. In these cases, even if there are no signs of fleas, a veterinarian may still diagnose a flea allergy based on hair loss patterns and any history of incomplete flea prevention.

Diagnosing Food Allergies in Dogs

Diagnosing food allergies in dogs can be a bit more challenging. It often involves extended elimination diet trials, during which a dog must avoid all contact with common food allergens.

Common food allergens in dogs include proteins such as chicken, beef, pork, egg, soy, and dairy. Merely selecting a “limited ingredient diet” or one with alternative proteins like fish or venison may not suffice. Even limited diets contain many sources of protein, one of which may be an allergen. Also, there’s always a chance of cross-contamination with ingredients from other diets, depending on the manufacturing process. 

To achieve accurate results, veterinarians typically recommend a controlled elimination diet. These can last between 8-12 weeks, during which dogs eat only a hypoallergenic diet prescribed by a veterinarian. These diets are produced in facilities that guarantee no cross-contamination, making them the gold standard for food restriction testing. After the elimination phase, specific protein sources are gradually reintroduced to identify the dog’s allergy. 

While there are blood tests available for diagnosing food allergies in dogs, they can be less accurate, which could lead to unnecessary food restrictions.(1)

Diagnosing Environmental Allergies in Dogs

Environmental allergies can also be more challenging to diagnose as dogs can be allergic to indoor allergens, outdoor allergens, or both. Providing a detailed history of your dog’s allergy symptoms can help when diagnosing environmental allergies, as the symptoms often change with the seasons. 

For example, dogs with mold allergies may be most itchy during winter, while those with pollen allergies may experience heightened discomfort in spring and summer. 

Physical location may also play a role. For example, if a dog with no history of allergies or itchy skin starts showing symptoms after moving to a different part of the country, veterinarians may suspect an environmental allergy.

There are both blood and skin exposure tests for environmental allergies, but many veterinarians use a dog’s response to treatment as a diagnostic tool, as well. 

It’s important to note that acute allergic reactions, such as bee stings, are distinct from allergies. Acute reactions characterized by local swelling, redness, and pain are diagnosed and treated differently. Hives in dogs are more likely to be associated with acute allergic reactions rather than allergic dermatitis. Acute allergic reactions are typically treated with injectable medications; once the swelling subsides, no further treatment is required.

Treatment for Allergies in Dogs

In most cases, dog allergy treatment focuses on managing the allergic response, rather than completely eliminating or curing the allergy. This means that while the symptoms can be minimized, the underlying allergy persists, and if treatment is stopped, the signs of allergy will return.

Since itchy skin is one of the most prevalent symptoms of dog allergies, most treatment plans involve medication targeting itch and inflammation relief. One common oral medication veterinarians often prescribe is Apoquel, a fast-acting allergy medication that starts controlling allergy itch in dogs within four hours.

Apoquel medication bottle

Your veterinarian may recommend additional treatment options, depending on what’s causing a dog’s allergies.

Treating Food Allergies

For dogs diagnosed with food allergies, veterinarians typically recommend a diet that excludes the specific protein they are allergic to. This can be the same diet used during the elimination trial or a novel protein diet such as fish, venison, rabbit, or even kangaroo.

Treating Flea Allergies

Dogs with flea allergies should be on year-round effective prescription flea prevention, available in both chewable and topical forms. Some flea preventatives require the flea to bite the dog for the medication to be effective, while others repel fleas altogether. Combining these two categories of medication may be necessary for dogs severely affected by flea allergies since no preventative is 100 percent effective at all times.

Treating Environmental Allergies

Environmental allergies often require a wide range of treatment options due to their prevalence and diversity. Prescription options are available for dogs with more severe environmental allergies, including oral medication (Apoquel), injectable medication (Cytopoint), and allergy desensitization treatment (commonly known as “allergy shots“) available in both injectable and sublingual forms. Allergy shots are tailored specifically to your pet and may involve higher upfront costs.

Your dog may also benefit from a specific therapeutic diet formulated to help enhance the skin’s natural protective barrier. For example, Royal Canin® Skintopic Diets provide targeted nutrition to support skin quality and coat health. These prescription formulas are clinically proven to manage skin itchiness in dogs and improve quality of life.

Royal Canin Skintopic dog food bag

Dogs with mild symptoms may benefit from over-the-counter human medications like diphenhydramine (Benadryl), cetirizine (Zyrtec), loratadine (select Claritin formulas), and others. 

However, avoid using decongestants or any products containing pseudoephedrine (like Claritin-D). Even small amounts of pseudoephedrine can be lethal to dogs.

Remember, it’s important to consult with your veterinarian before deciding on a treatment plan or administering any of these medications. Your vet can determine the most effective treatment plan for your dog’s specific allergies and symptoms, as well as the most effective dosage.

This is especially important in the case of over-the-counter medications, as the recommended dosages for humans may not be safe for pets. 

Dog Allergies: Pro Tips for Success 

In addition to medications, several measures can be taken at home to keep allergic dogs comfortable. If your dog is allergic to outdoor allergens, wiping their fur when they come inside, paying attention to the skin between and under their toes, can be helpful. Bathing them with a medicated shampoo every two weeks can also minimize allergy symptoms. Be sure to consult your veterinarian before using regular store-bought shampoos, as some can worsen allergies.

If your dog is scratching or licking their itchy skin raw, using an e-collar (cone of shame) or alternative can prevent them from further damaging their skin and developing a serious infection. This is particularly effective for dogs scratching at their ears or chewing their feet.

Dietary supplements rich in fish oils, ceramides, and other skin barrier protectants can also provide relief. For more recommendations, ask your veterinarian about whether prescription skin diets, supplements, or other options might help soothe your itchy dog.

While allergies in dogs cannot be completely cured, pet parents have many helpful options to help minimize discomfort and improve quality of life for allergic dogs. By tracking your dog’s allergy symptoms and consulting with your veterinarian on an effective treatment plan, you can ensure that your dog remains comfortable, healthy, and happy despite their allergies.


  1. Jackson HA. Food allergy in dogs and cats; current perspectives on etiology, diagnosis, and management. J Am Vet Med Assoc. 2023 Mar 18:1-7. doi: 10.2460/javma.22.12.0548