Allergies in Dogs: Common Allergens & Treatment

If your pup has allergies, they may be itching their skin all day, and even keeping you up at night with their licking and scratching. Or, maybe you’ve noticed digestive upset or “hay fever” type symptoms.

Either way, you’re probably trying to figure out how you can help your furry friend feel better. Here’s what you should know when it comes to your dog’s allergies.

What Do Dog Allergy Symptoms Look Like?

To understand allergy symptoms, it’s important to know what allergies are.

Allergies are an overreaction of your dog’s immune system. For example, if the immune system detects pollen or dust or an ingredient in your dog’s food, those substances get treated like a foreign invader — as if they were a virus or bacteria.

Part of the immune response is to release histamine, which results in a lot of inflammation. This may become apparent in the upper respiratory system, digestive system, or (very commonly) your dog's skin.

Inflammation causes redness and itchiness, and it disrupts the normal protective skin barrier. Between inflammation and trauma from your dog’s licking and scratching, secondary skin infections with bacteria or yeast are common.

Here are some of the most common allergy symptoms in dogs:

Red or itchy skin, especially on the paws, belly, groin, armpits, head, face, and ears.
Hives, bumps, rashes, or swellings on the skin.
Skin wounds, referred to as “hot spots” (they’re usually caused by your dog’s persistent scratching or licking the affected area).
Skin or ear infections.
Fur or hair loss.
Diarrhea, vomiting, or other gastrointestinal symptoms.
Scooting their rear end on the floor.
Red, itchy, puffy, or watery eyes.
Sneezing or a runny nose.
Coughing or wheezing.
Anaphylactic reaction, which may include facial swelling, sudden vomiting or diarrhea, difficulty breathing, collapse, and even death. Fortunately, this is not common — you’re very unlikely to see an anaphylactic reaction due to seasonal, flea, or food allergies. But if you ever notice these symptoms in your pet (especially after something like a bee sting, vaccine, or new medication), bring your dog to a vet immediately.

Your pet may display several of the symptoms above, or just one or two. Any of these symptoms, especially if they happen frequently, are enough to consider allergies as a possible cause. And, it's best to visit your vet to properly diagnose and treat your furry friend.

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What Is My Dog Allergic To?

Not all dogs with allergies have the same condition. Symptoms can range from mild to severe, and they may affect several areas of the body.

There are many different types of allergens your dog can be sensitive to. Some dogs may have just one type of allergy, while others may suffer from multiple allergies.

Below are common types of dog allergies.

Environmental & Seasonal Allergies in Dogs

Dogs with environmental allergies are affected by inhaled allergens in the home and outdoors. This includes dust, dust mites, pollens from trees, grasses, weeds, molds, and more. The list of potential allergens is very long, and may vary depending on which plants are found in your climate.

Usually, symptoms occur due to inhaling these allergens, but direct skin contact with allergens can also cause symptoms. Just like environmental allergies in humans, symptoms tend to be seasonal. But symptoms may worsen and become year-round over time.

Commonly environmental or seasonal allergies are inherited, in which case it’s known as “atopy.”

Flea Allergies in Dogs

Flea Allergy Dermatitis (FAD) — skin irritation and infections that occur secondary to this allergy — is the most common skin problem in dogs.

Technically, your dog isn’t allergic to fleas—they’re allergic to flea saliva. This is different from normal itchiness in response to a bug bite. Instead, dogs with flea allergies will compulsively lick and scratch after as little as 1-2 bites, often chewing their skin raw and causing an infection.

Diagnosing a flea saliva allergy can be tricky because you might not see the flea(s). For example, if your pup is out for a walk and a single flea jumps on and bites them but then falls off when your dog scratches, that one bite can cause a raging skin reaction that lasts up to a week!

Food Allergies in Dogs

Food allergies are not nearly as common in dogs as most pet parents think they are — in fact, food allergies only account for 10% of allergy-afflicted pets.

However, it’s still important to consider food allergies when figuring out what’s causing your dog’s symptoms. Your pup may be have an allergic reaction to just one ingredient, or several — and new food allergies can develop over time. This is similar to humans who are allergic to peanuts or shellfish — there’s nothing inherently wrong with the foods, it’s just that some individuals develop an allergy.

Common food allergens include proteins found in beef, lamb, chicken, soy, or wheat.

Dog food allergy symptoms often show up as digestive problems, but they also commonly cause skin issues that mimic environmental allergens.

It’s also important to note your pet may have symptoms due to a food intolerance. This is different from a true allergy because the immune system is not involved, so some allergy treatments won’t work for food intolerance. Instead, difficulty digesting or processing a certain ingredient may be to blame.

Other Allergies That Can Affect Dogs

Most allergic pets fall into one of the above categories. But there are other possibilities.

Contact allergies affect some dogs. For example, this might occur when your dog has an allergy to your laundry detergent and develops a skin rash after lying on their freshly washed dog bed. Usually, the parts of the body that touched the allergen will be affected, rather than the whole body. As described above, anaphylactic reactions are also possible.

And some pets may suffer from reactions to other inhaled substances like perfume or smoke.

What Causes Allergies in Dogs?

Allergies tend to be genetic or inherited. Unfortunately, this means allergies are difficult to avoid.

Some dog breeds that may be more susceptible include Bulldogs, Chinese Shar-Peis, Retriever and Terrier Breeds, Shih Tzus, and Lhasa Apsos. But any breed of dog may be affected.

Allergies often first show up when a dog is 6 months to 3 years old. You might notice allergies are seasonal, or that they get better or worse if you move to a new place.

How Are Allergies Diagnosed in Pets?

Allergy testing requires patience. There’s a process to go through to reach an accurate diagnosis — and therefore the best treatment option — for your pooch.

The first step usually involves ruling out other medical or emotional conditions that could cause similar symptoms. For example, microscopic skin mites cause skin symptoms that look like allergies, but certain allergy treatments will make skin mites get much worse! Also, an anxious or bored dog may lick or chew their skin, similar to how some humans chew their fingernails.

Testing for other conditions will probably start with a gentle skin or ear swab/scrape to look for bacteria, yeast, mites, or other abnormalities. Bloodwork (for example, to rule out a thyroid condition) and other diagnostic tests may be needed, too.

If allergies are suspected, here are some common next steps:

Evaluating for food allergies via a food trial. Blood tests are not as accurate for food allergies, so a food trial should be used. This is a strict diet on a type of food that is unlikely to cause allergies in your dog, for 1-3 months. It’s best to do this under your veterinarian’s guidance.
Evaluating for environmental allergies. Blood tests are common. Skin testing may also be performed, usually by a veterinary dermatologist. These tests help determine which environmental allergens your pup is most sensitive to. Often, these tests are customized to include allergens specific to your climate, state, or city.

How Are Dog Allergies Treated?

Unfortunately, there is no cure for allergies, but treatment is possible.

It’s important to remember that treatment means managing allergies, not curing them. Keeping this goal in mind will help you set realistic expectations, avoid frustration, and plan the most effective long-term management strategy.

Below are some treatment strategies.

Flea allergies: All allergic dogs should be on good quality flea control year-round. Remember, your pet could be affected by flea allergies even if you don’t see fleas on them. And small numbers of fleas can survive and bite dogs even during harsh winters.
Food allergies: Your furry friend must stay on a strict diet with a food that you know does not cause allergy symptoms. Unfortunately, that usually means common treats, table scraps, and even flavored medications are off limits. Your vet can help you find alternative medications and a hypoallergenic diet that may be better tolerated.
Environmental allergies: Unfortunately, environmental allergens are harder to control, since you can’t change the pollen count. Pets with atopy or seasonal allergies may need treatments and medications long-term — given either on a regular basis or just during flare ups, depending how bad their symptoms are. You can also consider immunotherapy (or desensitization therapy) for environmental allergies. This means weekly injections, which are customized for your pet after allergy testing. The allergy shots contain small amounts of the things your pet is allergic to, so your pup slowly builds up a tolerance. The downsides are that it can take many months to work and as many as 50% of pups won’t see a significant change in their symptoms. But for dogs with severe symptoms, it may be worth trying.
Secondary infections, wounds, and hot spots: No matter which allergies your dog has, all resulting skin conditions must be treated promptly. Otherwise, they tend to get worse.

Other things you can do for your allergic dog, including home remedies, include:

Watch the pollen/allergy counts and avoid keeping your pup outside for too long when counts are high.
Keep the home clean and change air filters regularly.
Bathe your dog with pet allergy shampoos, such as soothing aloe and oatmeal, or medicated with allergy-relieving ingredients.
Skin ointments or creams for small flare ups. Check with your vet for safe options.
Skin and allergy supplements, such as omega fatty acids or probiotics.
Wipe your dog’s paws and belly with a clean cloth or pet wipe after their walks to remove pollen and other allergens.
Use antihistamines such as Benadryl. Check with your vet for a safe formulation and dose for your individual pet. Never buy products that also contain decongestants or other ingredients.

Allergies can be frustrating — both for you, and for your pup who can’t seem to find relief from their itchiness.

Fortunately, with patience, vigilance, and the right treatment plan for your individual furkid, you can really make your pup feel better so they can enjoy all their favorite activities with you — itch free!