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

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 single dog paw 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 4 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

All Dogs Deserve a Comfortable Retirement: Pain Relief for Older Dogs

Hi, I’m Dr. Karyn! Read my introduction to learn more about me and my five funny dogs, Poppy, Bailey, Kodah, Ned, and Fred....

300 Girl Dog Names: Fun, Fierce & Fabulous Female Dog Ideas

Adding a new dog to your family is an exciting and rewarding experience. Dogs are special animals who bring joy to many, and...

25 Dog-Friendly Activities in Detroit: Places to Take Your Pup to

The world has gotten much more dog-friendly in recent years, so the next time you head out on vacation or out of town...

Can Dogs Eat Bay Leaves? Vet Approved Facts & FAQ

Dogs often have a way of charming their way to eating their humans’ table food. While many of us find them irresistible and...

More related

Hanover Hound Dog Breed: Info, Pictures, Care Guide & More

Hanover Hounds are an extremely rare dog breed used almost exclusively for hunting. Companion Hanover Hounds are few and far between, too. This...

Grain vs. Grain-Free Dog Food: Which One’s Better? Facts & FAQ

The grain versus grain-free debate is a controversial and heated topic in the dog world, especially when it comes to specialty dog food....

Why Do Puppies Eat Their Poop? 7 Reasons & How to Stop It

Puppies are adorable, fluffy little goofballs, but all that charisma and charm goes out the window when you see them eating poop. However,...

Nulo Dog Food Review: Recalls, Pros & Cons

Review Summary Nulo was created with quality care for dogs in mind. Its founder realized that there weren’t enough care options available for...

Keep reading

10 Best Dry Dog Foods in Canada in 2025: Reviews & Top Picks

Feeding your dog is one of the top priorities for all dog owners, and finding the perfect dog food that will keep your pup happy and in good health is essential! But whether you’re looking to switch your dog’s food...

labrador dog eating food indoor

What Foods Reduce Anxiety in Dogs? 10 Vet-Verified Nutrients & Methods to Help

It can be quite heartbreaking watching your dog deal with anxiety and stress. Your first call should be to your veterinarian, particularly if the anxiety is severe because food alone is unlikely to solve the issue. That said, diet can...

jack rusell terrier dog eating kibble from a slow feeding bowl

RAWZ Dog Food Review 2025: Recalls, Pros & Cons

Review Summary The RAWZ pet food brand is relatively new and is making waves in the industry as one of the most committed brands in terms of quality and taste. Most of their ingredients are sourced either in the United...

Dogster_RAWZ Dog Food Review

Vets Reveal Safest Way to Serve Salmon to Your Dog

If you’ve ever caught your pup giving you that “please share your salmon” look, you’re not alone. Most dogs go wild for this flavorful fish, and thankfully, it can be an incredibly healthy treat. But here’s the catch: serve it...

dog food with salmon

Nutra-Nuggets Dog Food Review 2025: Pros, Cons & Recalls

Review Summary Nutra-Nuggets is a pet food company that’s under the umbrella of Diamond Pet Foods. It has two main lines of food—US and Global. The types of dog food available through each line are pretty similar, and the ingredient...

Dogster_Nutra-Nuggets Dog Food Review

9 Best Puppy Foods for Australian Shepherds in 2025 – Reviews & Top Picks

Every puppy is different, and Australian Shepherds have their own quirks. These large, active dogs need a lot of nutrition to keep them playing and growing all day long! These reviews go over a few of our favorite puppy foods...

dog eating from a stainless bowl

10 Best Canned Dog Foods for Picky Eaters in 2025: Reviews & Top Picks

While it can be a mystery as to why some dogs are picky, finding dog food that a picky dog enjoys can feel like an even greater mystery to solve. Many dog owners have found solutions with meal toppers and...

shih tzu dog getting wet food from owner at kitchen

Can Dogs Eat Mussels? Vet-Approved Benefits & Safety Tips

Dogs can eat mussels in moderation. Mussels are high in protein and other nutrients that may benefit your dog; however, they don’t provide everything your dog needs, so they should only be considered an occasional treat. It’s best to steam...

Can Dogs Eat_Mussels