Everything to Know About Allergic Reactions in Dogs

A dog sniffing and itching in a field of flowers and grass.
A dog sniffing and itching in a field of flowers and grass. Photography ©bruev | iStock / Getty Images Plus.

Do you know what to do if your dog is having an allergic reaction? First, it’s important to know that there are many different types of allergies in dogs, including environmental allergies, food allergies and allergies to insect bites or stings, medications, flea preventives or vaccines. Here’s everything to know about dog allergic reactions and how to handle an allergic reactions in dogs:

First, why do allergic reactions happen?

A dog with a flower on his nose.
Allergic reactions happen when a dog’s body tries to destroy a substance (like pollen), even though it isn’t harmful. Photography ©Kira-Yan | iStock / Getty Images Plus.

An allergic reaction occurs when the immune system overreacts to something. The body releases antibodies and histamines in an effort to destroy the invading substance, even though the particular substance (food, pollen, etc.) isn’t actually harmful.

What types of allergies might dogs have?

With food allergies, dogs are allergic to one or more food ingredients, commonly proteins or carbohydrate sources.

Environmental allergies are caused by anything your dog inhales, ingests or absorbs through his skin, including dust, pollens, grass, mold, smoke and more.

Dogs are even allergic to flea bites, with some dogs developing more severe reactions to these parasites than others (see below).

What do mild allergic reactions in dogs look like?

Food and environmental allergies might cause troubling reactions like gastrointestinal upset (vomiting and diarrhea), itchy skin, ear infections, runny eyes or sneezing, but such reactions are rarely emergencies.

If you notice possible allergy signs like chronic itching or stomach upset, it’s best to see your veterinarian, who will be able to root out the cause of the symptoms.

When is your dog’s allergic reaction an emergency or life-threatening?

Other allergic reactions, however, can be life-threatening. Dogs could be allergic to many things, but common culprits of allergic reactions in dogs include insect bites and stings, and vaccines. It’s important to learn how to recognize the signs of a severe allergic reaction in dogs, and what to do if you even suspect an allergic reaction.

These allergic reactions in dogs can manifest as mild or severe. A mild allergic reaction might just be a little bit of facial swelling (eyes, muzzle or near the ears) or a few hives on the skin. Hives are small, raised bumps on the skin, which might be itchy. It can be hard to see hives if your dog has longer fur, but you might be able to feel them on the body.

A severe allergic reaction, called an anaphylaxis, is a true emergency. With anaphylaxis, you might see facial swelling and hives, as well as vomiting, weakness, difficulty breathing, pale gums and sudden collapse. Untreated, dogs experiencing anaphylaxis could go into shock and could even die. 

What to do for a severe allergic reaction

“Because anaphylactic reaction can be rapidly life threatening, seeking veterinary attention is recommended,” says Claude Lessard, DVM, an emergency veterinarian at Veterinary Medical and Surgical Group in San Juan Capistrano, California.

Waste no time getting your dog to a vet. This is true even for mild reactions because your dog’s symptoms might progress. If your dog is experiencing an allergic reaction during normal business hours, head directly to your vet hospital. It helps to call the hospital to let them know you think your dog is having an allergic reaction and that you’re on your way. If your dog seems to be experiencing an allergic reaction after hours, take him to an emergency vet.

“Because some types of allergic reactions can be rapidly life threatening, we always advise to have your pet evaluated by a veterinarian,” Dr. Lessard says. “In most cases, the veterinarian will give injections of an antihistamine medication, such as diphenhydramine, and an injection of a steroid to stop the reaction. For anaphylactic shock, other lifesaving treatments may be indicated, such as administration of IV fluids, epinephrine and other treatments.”

Should you ever treat your dog’s allergic reaction at home?

Many dog owners wonder if they should administer an antihistamine like diphenhydramine (Benadryl) if they suspect that their pet is having an allergic reaction. Dr. Lassard does not recommend attempting to treat your dog’s allergic reactions yourself at home without explicit instructions from a veterinarian.

“Oral Benadryl is often not enough to treat an allergic reaction and can be detrimental if it delays seeking appropriate care,” she says. “If your dog has an allergic reaction, your veterinarian may recommend a specific dose for your dog to be given in case of a recurrent reaction. It is not recommended to give any medications without veterinarian supervision.”

What if your dog has an allergic reaction to a vaccine?

If your dog ever experiences an adverse reaction after receiving vaccinations, head back to the clinic, calling to let them know you are on your way and that your dog appears to be having an allergic reaction following vaccinations.

In the future, always tell veterinary caregivers that your dog has experienced a vaccine reaction. For some cases, the vet might want to pretreat your dog with certain medications before vaccinating to prevent another reaction. Or, the vet might recommend avoiding all future vaccines for your dog.

Thumbnail: Photography ©bruev | iStock / Getty Images Plus. 

Battling allergies yourself? Here’s how to get through allergy season >>

Read more about dog health and care on Dogster.com:

6 thoughts on “Everything to Know About Allergic Reactions in Dogs”

  1. My 4 years old mixed breed dog yesterday had an allergic reaction to Imidocarb dipropionate. Two weeks ago it was injected under the skin and a big lump formed in which lymph accumulated, and yesterday veterinarian repeated the injection into a muscle and my dog’s face started ​​swollen, she looked very sick, I am glad she is okay now. Maybe you could tell me, wheter the doctor did the right thing by repeating imidocarb ?

  2. Pingback: Blood Tests May Detect Allergies in Dogs – My Pets

  3. My 4 year old mini labradoodle has being sneezing for 7 months.
    It was horrific the day it started, reverse sneezing. I thought he was having seizure. Too him to vet they wanted a CT scan and scope. Both 1200 each. So we did the CT, all good and that is last I heard from Vet? I took him to 3 other vets, same diagnosis, CT and scope. Contacted the first vet. Dr said teeth good, ct good, come in we can talk about homeopathic remedies? I even tried those which made my dog sicker, vomiting rapid sneezing. We are snow birds so in another area and the sneezing is not as bad, how ever he is not eating well. Raw food has been fed always. He is so picky i have tried over 8 brands and toppers, goat milk, pre pro biotic which has helped with his runny stools. Back home he eats a raw if he likes it 8 months than can go 5 days with nibbles till i switch and find one he will stick with. Can not get his food here in the USA. I do not know what to do other than go home to more snezzing? I have even last year cooked for him with DIY food just for dogs, loved it but was to vet every 3 weeks with constant runny stools? I am lost.

  4. Pingback: Blood Tests May possibly Detect Allergies in Canine – Smart Pet Club

  5. Pingback: Blood Tests May Detect Allergies in Dogs – Pet Supply Deals

  6. Pingback: Top 15 Best Pro Pet Supplies Dog Shampoo Options

Leave a Comment

Your email address will not be published. Required fields are marked *

Get Dogster in your inbox!

Stay informed! Get tips and exclusive deals.

Current Issue

This error message is only visible to WordPress admins
There has been a problem with your Instagram Feed.


Follow Us

Shopping Cart