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Allergy Bumps on Dogs: Urticaria & Hives Explained (Vet Answer)

Dr. Lauren Demos (Vet)

By Dr. Lauren Demos (Vet)

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Written by

Dr. Lauren Demos

DVM (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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Bumps on your dog’s skin can be challenging, and, moreso, concerning. What caused the bump? Will it hurt my dog? How concerned should I be?

One of the more common bumps encountered in our canine companions is a condition called, urticaria, which is the medical term for hives. Hives are basically a swelling in the skin, resulting from an immune reaction to a foreign substance, along with the body’s attempt to prevent that foreign substance from causing damage.

Unfortunately, with hives, sometimes this immune reaction is caused by substances that aren’t actually harmful, and the reaction is a bit of overkill to what would otherwise be a harmless situation. A major downside of hives is that, on the more severe end of the spectrum, the reaction can become life-threatening, and quite quickly.

Knowing more about hives and the condition of urticaria, the actual process by which hives are formed in the body, triggers that can cause hives in dogs, and how they might be treated or prevented, can all be very helpful knowledge to have. Especially knowing what may be signs of an impending hive emergency.

Read on to learn more about urticaria and hives in dogs, what these allergy bumps might be telling you, and what to do about them!

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Urticaria and Hives in Dogs Explained – What Are They?

Urticaria is the medical term for hives, which are raised skin welts (or bumps). They are caused by a reaction of various immune cells that live within the skin, surveilling for any foreign invaders that might lead to potential bodily harm. Hives represent a reaction by these cells, which is swelling and inflammation of the associated skin.

Hives are often very itchy, and can somteimtes become quite red, due to the inflammation. They can develop almost anywhere on the skin, but are more common on the back, neck, muzzle, face, and legs. Hives can appear (and disappear) quickly.

In mild cases, hives may not require treatment, just close monitoring at home. However, severe cases may progress to a condition called anaphylaxis—in which the entire body becomes involved in the allergic reaction, and anaphylactic shock (and death) can occur. In such severe cases, emergency treatment is needed.

close-up photo of a dog allergic bumps_Todorean-Gabriel_Shutterstock
Image Credit: Todorean-Gabriel, Shutterstock

What Are the Causes of Urticaria and Hives in Dogs?

1. Vaccines

Some vaccines in dogs can lead to allergic reactions that present as hives. This can happen almost immediately after a vaccine, or a delay may occur. If you notice this happening after your dog receives a vaccine, alert your vet immediately. This may require treatment, and your vet will also want to know this happened, in order to make decisions about how to best vaccinate your dog in the future.

2. Shampoos

Some topical products, including shampoos, can sometimes set off an allergic reaction in the skin, leading to hives.

3. Medications

Similar to vaccines, allergic reactions can occur after dogs receive some medications. Just like vaccines, it is important to alert your vet as soon as you notice this, because the medication may no longer be suitable for your dog.

4. Insect Bites and Stings

Insect bites and stings from bees, wasps, hornets, fleas, spiders, chiggers and other bugs can all potentially lead to hives in dogs. Some dogs may only get a few hives, while others may have the same bite or sting and develop many hives as a result. It can, therefore, vary widely depending on the particular dog. Hives from insect bites and stings are most commonly found around the face and muzzle of a dog.

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Where Are the Signs of Urticaria and Hives in Dogs?

Signs of urticaria and hives in dogs can vary widely. Often, individual dogs will have very different responses, depending on their immune systems and genetics.

  • Skin redness
  • Raised skin welts (hives)
  • Facial swelling, including eyes and muzzle
  • Vomiting
  • Diarrhea
  • Drooling
  • Lethargy or acting dull
  • Hiding or other changes in behavior
  • Fever
  • Difficulty in breathing
  • Difficulty eating
  • Itching

What Are the Potential Dangers of Urticaria and Hives in Dogs?

The dangers of any allergic reaction, such as urticaria, or hives, is that if the immune system cannot stop the allergic reaction, it can progress to anaphylactic shock.

Anaphylactic shock is a condition in which the entire body becomes involved in an overexuberant immune response, and as a result, various organ systems, such as the kidneys, lungs, and others, start to shut down. If not treated immediately, this can result in death.

Even mild cases of hives, once triggered by a certain substance, will likely recur with repeated exposure to that substance. Often, each time exposure occurs, the reaction will get worse.

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Image Credit: Jagodka, Shutterstock

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Frequently Asked Questions (FAQs)

Are hives contagious?

No, the condition itself is not contagious. However, the same inciting cause may lead to hives in other exposed dogs.

How are urticaria and hives diagnosed?

Generally, a clinical history and a physical exam are sufficient to diagnose the condition.

What are the treatment options for urticaria and hives in dogs?

It depends on how severe the hives are. Sometimes, no treatment is required. In more severe cases, sometimes an anti-inflammatory medication will be given or prescribed. In very severe cases, including anaphylactic shock, sometimes IV fluids, along with anti-inflammatory medications, must be used to stabilize the dog. This will often require hospitalization and close veterinary monitoring for the duration of treatment.

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Urticaria and hives can sound straightforward in dogs, but in reality, they can quickly become a complicated and life-threatening condition. Don’t hesitate to let your vet know if you see hives occur in your dog, and make sure to note what your dog was doing, eating, or had been exposed to at the time. This will help to narrow down what may have caused the reaction.

Many dogs with hives will not require treatment. However, if you see any changes in your pet’s breathing, if the hives or swelling becomes widespread, or if your pup simply seems too uncomfortable, never hesitate to reach out and get the help they need.

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Featured Image Credit: Yekatseryna Netuk, Shutterstock

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