Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

8 Vet-Verified Signs of an Allergic Reaction in Dogs to Be Aware Of

Share

dog scratching its body

Allergies are, unfortunately, fairly common in dogs. Dogs can be allergic to a variety of things, including dust mites, pollen, mold, insect bites and stings, and various kinds of food. The signs of allergies can range from mild to severe and potentially life-threatening, so it’s important to be familiar with the possible signs and know what to do if you think your dog may be suffering from an allergy. We’ll go over a few common signs of an allergic reaction in dogs and what you can do to help your dog if you notice them.

divider dog paws 2 oct 2024

The 8 Signs of an Allergic Reaction in Dogs

1.  Hives

Hives (also known as urticaria) are small red raised bumps or larger welts that appear on a dog’s skin and are caused by an allergic reaction. Hives can appear anywhere on the body and are usually itchy. Although hives are relatively uncommon in dogs, they are most commonly caused by a reaction to insect bites and stings, shampoos, and medications.

Typically the wheals appear quickly and can often disappear just as fast. However, there is a risk that the allergic reaction can worsen leading to dangerous swelling or anaphylaxis, so it’s always best to seek veterinary advice if your dog has developed hives.


2. Itchiness

Skin itchiness is the most common sign of allergies in dogs. Therefore, it’s important to pay attention to your dog and look for excessive scratching, licking and chewing. It’s also helpful to examine their skin periodically to look for redness and rashes. Environmental allergies (such as pollen and house dust mites), food allergies and flea allergic dermatitis can all cause skin irritation and itchiness.

shiba inu dog scratching its ear
Image Credit: MitchyPQ, Shutterstock

3. Hair Loss

Because allergies often affect skin health, you may notice hair loss and even bald patches on your dog. If your dog is itchy they may damage the skin or break and pull out hairs when they are scratching and chewing at themselves.


4. Face Swelling

Sometimes, allergies can cause certain parts of your dog’s body to swell. Swelling is most commonly seen around the face, and you may notice your dog’s muzzle, eyelids, ears, and mouth become red and swollen.

While face swelling may sound scary, there are varying degrees of swelling that range from mild to severe. Mild cases of facial swelling may resolve with minimal treatment but more severe swelling can become life-threatening and will require immediate medical attention. Always contact your vet straight away if your dog has a swollen face.

Did you know you can speak to a veterinarian without having to travel? Just head over to PangoVet. It's our online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content Savings V1


5. Coughing and Sneezing

Inhaled allergens can also affect a dog’s respiratory system and cause irritation and inflammation.

Similar to humans, dogs can sometimes start to sneeze and have a runny nose when they have allergies.They may also wheeze or cough. If your dog is showing any of these signs then you should get them checked out by your vet and they can prescribe appropriate medication to help them manage their allergy symptoms. Many other health conditions can cause similar signs and these need to be ruled out.

black labrador dog in field sneezing
Image Credit: RHIMAGE, Shutterstock

6. Vomiting and Diarrhea

Most dogs will get an upset stomach if they eat something that they’re allergic to, and they can experience vomiting, diarrhea, gassiness, and tummy pain. Common food allergens for dogs include chicken, beef, and dairy.

When dogs have food allergies, they can show signs other than an upset stomach. They may also experience itchy skin and recurrent skin infections.


7. Chronic Ear Infections

Dogs with allergies are unfortunately also prone to getting ear infections. Ear infections can be secondary to food allergies and environmental allergies.

If your dog has signs of an ear infection, such as increased discharge and irritation, it’s always best to take them to your vet for a proper examination. Ear infections can range from mild to serious cases that can even rupture your dog’s eardrum.


8. Anaphylaxis

Anaphylaxis is an immediate, severe and sometimes life-threatening allergic reaction. Signs can include breathing difficulties, swelling of the face and throat, severe vomiting or diarrhea, tremors, collapse and seizures.

Signs come on very quickly and severely so rapid veterinary attention is vital, especially if your dog is showing signs of shock or difficulty breathing.

sick old dog on the couch with blanket
Image Credit: Lindsay Helms, Shutterstock

divider dog paws 3 oct 2024

How Can I Know if My Dog Has Allergies?

As there are so many different allergens and types of allergic reactions it’s important to consult with your veterinarian for a proper diagnosis and treatment plan.

Sometimes, it’s easy to identify allergens. For example, bug bites and stings are sometimes obvious culprits because they usually cause swelling near the area of the bite or sting. Flea allergic dermatitis is also usually fairly easy to diagnose. However, reactions to environmental allergens, like pollen, can be more difficult to detect. Diagnosis usually starts with ruling out other skin conditions that cause similar signs such as parasites and infections.

If your vet is suspicious of food allergies they may ask you to put your dog onto an elimination diet which involves feeding them a new food and source of protein that they have not had before, or a hydrolyzed diet where the proteins have been broken down so small they don’t react with the immune system.

Allergy skin tests and serology (blood) tests are available when other conditions have been ruled out to pinpoint the environmental allergens that your dog is reacting to.

divider dog paws 3 oct 2024

Conclusion

Dogs can be allergic to a wide variety of things, and they can develop allergies at any point of their lives. Allergies can manifest in various ways from mild signs to severe life-threatening anaphylaxis. Understanding the common signs of an allergic reaction and knowing when to seek veterinary care helps ensure your dog remains healthy and comfortable.


Featured Image Credit: ElenaYakimova, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Dogster’s Weekly Photo Contest Winners: My Best Trick (April 16, 2026)

Every week our team gets the privilege of sorting through our readers photos to choose what dogs will win this weeks contest! See...

From Grief to Gratitude: How One “Potato” and a Road Trip Changed Everything

The “COVID Puppy” phenomenon is a well-known chapter of the pandemic, but for Alexis Walling, the arrival of a tiny, wrinkled English Bulldog...

Why Dogs Play Too Rough — And the Simple Fixes That Prevent It From Becoming a Problem

A dog that plays too rough with others is a problem that builds fast. One minute, the dogs are running and chasing, the...

Ricky Gervais Says: It’s Time to Release The Dogs

As activists prepare to carry out the biggest Open Rescue in the history of animal welfare, Ricky Gervais says, “it’s time to release...

More related

Do Hypoallergenic Dogs Exist? What Science Says

Hypoallergenicity has become an essential focus in the pet world in recent decades as breeders look for new ways to cater to allergy-suffering...

How to Feed a Puppy: 10 Vet-Approved Tips

Puppyhood is an important time in a dog’s life that’s marked by significant growth and development. Puppies have many needs and require a...

Are You Allergic to Dog Dander? 12 Vet-Approved Things to Do

It was a long-held misconception that when you have pet allergies, you are allergic to the animal’s hair. In truth, if you are...

Can I Groom My Own Dog? 12 Vet-Approved Care Tips

Taking your dog to the groomer every 4 to 6 weeks is a great way to keep up with their coat and decrease...

Keep reading

9 Best Non-GMO Dog Foods in 2026: Reviews & Top Picks

There are so many different types of dog foods on the market. From “grain-free” to “holistic” to “human-grade,” how do you choose the best one for your canine pal? Many marketing terms are used on dog food labels nowadays, and...

Gizmo white fluffy dog with Ollie dog food box

Buying Dog Food In Bulk: Benefits & Risks

According to statistics, the typical American dog owner spends an average of $1,380 annually on their dog’s basic expenses.1 While our pooches deserve the world, $1,380 is a lot. As such, any avenue that allows us to save on pet...

dog food_Shutterstock_Ekaterina Markelova

9 Best Dog Travel Bowls in 2026  – Reviews & Top Picks

Dogs often make some of the best travel companions. With so many dog-friendly places to visit, you can plan all kinds of trips with your dog. When traveling with your dog, it’s important to pack several essential supplies to make...

Border collie puppy drinking water from bowl in a park

Can Dogs Eat Cherries? Vet-Verified Facts & Considerations

You’re reading this for one of two reasons: Either your dog scarfed down a few cherries, or you’re looking to add fresh foods to their diet. So can dogs eat cherries? The good news is that yes, your dog can...

Can Dogs Eat_cherries

Just Food For Dogs Review 2026: Our Expert’s Opinion

Dog owners are often on a constant quest to find the perfect dog food for their doggies. With many options available today in the dog food market, it can sometimes get confusing. Dry dog food manufacturers offer plenty of promises...

Just Food For Dogs Dog Food

Can Dogs Eat Fruit Snacks? Vet-Verified Nutrition Info & Risks

If you have kids in the house, there’s a good chance you also have fruit snacks lying around. Fruit snacks are a fan favorite with the little ones (and adults as well!), so it’s wise to keep them handy. But...

Can Dogs Eat_fruit snacks

Why Does My Puppy Eat So Fast? 5 Vet-Reviewed Reasons & Advice

Bringing a new puppy into your home is always exciting, but along with the good can sometimes come some bad. Your puppy may exhibit some behaviors that you need to train them out of, like chewing on absolutely everything or...

Great Dane Puppy Eating

Easy Dog Treat Recipe: Mini Turkey Sliders (Vet-Approved)

The ingredients for this mini turkey slider dog recipe are likely the same ones you use for your own burgers. With your dog at your side, burger night can be even more fun! Mini Turkey Sliders Recipe This simple recipe...

Love Dogs? So Do We! Join the Dogster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Dogster Email Newsletter