Why Is My Dog's Body Covered in Bumps or Welts?

Updated on January 31, 2018
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Adrienne is a former veterinary hospital assistant, certified dog trainer, behavior consultant, and author of "Brain Training for Dogs."

Bumps or welts on your dog's body may be caused by a number of environmental triggers.
Bumps or welts on your dog's body may be caused by a number of environmental triggers. | Source

What Are These Bumps, Hives, or Welts on My Dog's Skin?

Urticaria is the medical term used to denote the presence of hives, welts, or wheels on a dog's skin. The skin rash presents as uncomfortable raised, red, itchy bumps. The welts can be localized on the dog's head, legs, belly, or back, or they can be widespread all over the dog's body and may come and go. Some dog owners describe the welts as dime-sized bumps on the dog's skin.

While there are many causes of welts in dogs, they often tend to result from an acute (arising suddenly) allergic reaction. A common culprit can be vaccinations, which is why vets often recommend keeping an eye on the dog for the first few hours after receiving shots. Other causes are from allergic reactions and exposure to certain types of plants, insect bites, household chemicals, medications, foods, and even stress. In some cases, the presence of welts may be indicative of other medical conditions. This article will focus on welts triggered by allergic reactions.

Common Causes of Welts on Dogs

Grass Pollen
Insect Bites or Stings
Dust Mites
Food and Medication
Misc. Environmental Allergens
Mold Spores
Chemical Exposure

Why Does My Dog Get Welts on Their Body?

When it comes to allergic reactions, welts can form when there is direct contact with an irritant. In this case, it's called "contact dermatitis," and the allergic reaction is mostly localized to the area that came in contact with the allergen. The welts or rash will, therefore, often show up on the dog's feet and the belly area if the dog happens to lie down on the trigger. Inhaled allergens such as grass pollen, dust mites, or mold can also cause welts, as well as insect bites. Sometimes, the actual trigger may be difficult to pinpoint and the underlying cause of the welts on the dog's skin will remain a mystery. A veterinary dermatologist may test for some common allergens, but the process can be costly and challenging at times.

Above: Testing a dog for allergies as they do in human medicine with transdermal injections.
Above: Testing a dog for allergies as they do in human medicine with transdermal injections. | Source

What Causes Welts?

When the dog's immune system reacts to an allergen, mast cells in its bloodstream release the compound histamine. Histamine triggers small blood vessels under the dog's skin to leak. The accumulated fluid, therefore, forms large welts.

Welts Can Indicate a Risk for Complications

One concern about welts is that they can sometimes be accompanied by swelling of the lips, nose, and eyes, which is medically termed angioedema. The eye swelling may be so severe that a dog cannot open its eyes, and these cases may require antihistamines and injectable steroids. Serious cases may also spread to the throat (laryngeal edema), which can block the dog's airway and lead to anaphylactic shock. Other accompanying symptoms may include:

  • vomiting
  • abdominal pain
  • diarrhea
  • shock
  • pale gums
  • cold legs
  • incoordination
  • sudden collapse
  • convulsions
  • death

In an emergency situation, time is of the essence. According to the Merck Veterinary Manual, dogs can die from anaphylaxis within minutes. These dogs need immediate veterinary attention which typically requires a shot of life-saving epinephrine. For those curious to know, yes, they do make epi-pens for dogs!

Respiratory distress can occur if the angioedema involves the nares, larynx, or pharynx.

— Karen A. Moriello, DVM, DACVD
Time is of the essence in a veterinary emergency.
Time is of the essence in a veterinary emergency.

Veterinary Treatment for Welts in Dogs

In order to address welts in dogs, the underlying allergy needs to be pinpointed. Benadryl is an antihistamine that blocks the release of histamine and can help provide relief. According to veterinarian Dr. Christine M.:

Plain Benadryl (diphenhydramine) can be given at a dose of 1 mg per pound of body weight every 12 hours until the dog's symptoms are gone.

It's always best to consult with a veterinarian before giving Benadryl to dogs and to discontinue its use if the dog shows behavior changes such as excitement or lethargy. Benadryl should not be given to dogs suffering from glaucoma. Other prescription medications include Claritin (loratadine) and Atarax (hydroxyzine), which are to be given under the guidance of a veterinarian.

Prescription Steroids

For severe reactions, steroids are sometimes given as a shot or as an oral medication (i.e., prednisone), but these drugs can have uncomfortable or severe side effects at times and suppress the immune system. In some cases, the dog may develop welts again once the steroid is out of its system.

Antibiotics for Secondary Infections

When dogs have rashes, the constant itching and scratching may cause lesions and secondary bacterial or yeast infections; this may require a course of antibiotics. A veterinarian will need to diagnose these secondary skin conditions by analyzing a skin sample under the microscope. The infections are often treated with antifungal or antibacterial shampoos such as chlorhexidine shampoo for bacterial infections and Malaseb shampoo (an antifungal).

It is important to find out which environmental allergen is triggering your dog's welts.
It is important to find out which environmental allergen is triggering your dog's welts. | Source

Natural Remedies for Nonsevere Dog Welts

  • Omega-3 Fatty Acids: Omega-3 Fatty Acids are also beneficial for the skin, but may take some time to kick in and provide relief. Veterinarian Dr. Kara recommends combining fatty acids and antihistamines as they are more effective in combination rather than when used individually.
  • Bathing Under Cool Water: Bathing may provide relief as it minimizes the time an allergen is in contact with the skin (pollen and grass accumulate on the skin). Oatmeal baths are soothing for dogs with allergies also.
  • A Hypoallergenic Diet: If the vet suspects that the welts derive from a food allergy, a special hypoallergenic diet may be recommended. This means no more table scraps or treats. Common prescription diets often contain novel proteins a dog has not been exposed to before. Hypoallergenic diets need to be followed for at least 2 to 3 months or more for the effects to be seen.


This article is not meant to be used as a substitute for veterinary advice. If your dog has welts, please see your veterinarian.

© 2016 Adrienne Janet Farricelli


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    • profile image

      Gina Auton 7 months ago


    • profile image

      Jenny 14 months ago

      Thank you. Helpful article!

    • alexadry profile image

      Adrienne Janet Farricelli 22 months ago from USA

      Thanks all! This is important information to be aware of as dogs can be prone to allergic reactions and welts in dogs may not be readily identified as they look different than welts in humans.

    • DDE profile image

      Devika Primić 23 months ago from Dubrovnik, Croatia

      I like the way you write about our friendly pets. Informative and always useful.

    • Karen Hellier profile image

      Karen Hellier 23 months ago from Georgia

      Interesting article. I have never noticed welts on my dog's body but she is 11 and has had hot spots and fatty tumors. Thanks for this information though. Very thorough article.

    • ladyguitarpicker profile image

      stella vadakin 23 months ago from 3460NW 50 St Bell, Fl32619

      Very interesting article and good advice. I have always used benadryl for my dogs. I am lucky my smaller dogs do not seem to get much of anything.