Hives on Dog’s Belly, Back, or Head: Signs and Treatments

This article was updated on September 19th, 2023

One day, my dog ate some moldy carrot shreds. An hour later, he had hives on his muzzle and swelling around his eyes. As a veterinarian, I recognized it was an allergic reaction and gave him antihistamines. Hives in dogs can appear anywhere on the body, including the belly, back or head. In this article, we’ll discuss hives, how to recognize them, and what causes them to appear on your pooch. Then, I’ll explain how to treat hives on your dog and how to differentiate them from other skin conditions. 

Overview of hives on the belly, back, or head of dogs

Hives, or urticaria, are raised red bumps on the skin. They usually appear suddenly as part of an allergic reaction. When a trigger like pollen, an insect bite, or a food antigen causes a response, the body releases histamines in the skin causing localized inflammation and itchiness.

You’ll usually notice hives around your dog’s head, belly, or back, but they may occur anywhere. The bumps can range from about ½ to several cm in diameter. Once they appear, they may last for several minutes to a month or more depending on the underlying cause

If you have a dog with thick or long hair, hives can be hard to see unless they’re on less hairy areas like the belly or in more visible areas like the head or back. If the bumps appear under the fur, you may notice a group of small, raised hair tufts. The bumps may or may not be itchy.  If your pooch is uncomfortable, try bathing him in cool water to soothe his skin. You can also try an oatmeal bath or apple cider vinegar spray. Always consult with your vet before trying natural remedies at home.

Hives are usually self-limiting and will resolve without significantly impacting your dog’s health. However, once your dog has an allergic reaction to a particular trigger, the reactions tend to increase in severity with repeated exposure.

If the hives persist, it’s a good idea to visit the vet and try to determine the trigger. The condition may be linked to a food sensitivity or environmental allergen. Immediately take your dog to the clinic any time the hives and swelling spread to the face or throat, He may be having a life-threatening anaphylactic reaction.

Signs of hives on a dog’s belly, back, or head

Hives are caused by a localized inflammatory response to a trigger. The possible signs include:

• Raised, red wheals on the skin or mucous membranes, as shown on the belly of this dog:

Flea bite dermatitis on a dog. Notice the red wheals that appear on the stomach’s skin surface. In this picture below, small red wheals appear on a dog’s back in response to flea bites.

• Extreme itching/scratching
• Swelling(angioedema)

This dog pictured above had an anaphylactic reaction. After treatment, notice the lingering angioedema around the eyes. The bumpy contour on top of the head suggests hives under the hair.

• Excessive drooling if swelling is around the face/mouth
• Puffy, swollen face 

English Bulldog with a swollen face and eyes due to allergies the reaction may begin as several wheals that coalesce to create generalized swelling. Click here to view pictures of hives on dogs.

Can hives be treated at home?

Many times, hives are treatable at home, but you should consult with your vet. He can advise you about home remedies and whether to give your furbaby over-the-counter antihistamines like Benadryl. 

To treat your dog:

• Remove the allergic trigger(if possible), 
• Apply cold compresses or use a cool bath to reduce inflammation/itching and soothe the skin
•  Give your dog antihistamines if directed by your vet

Causes of hives on the belly, back, or head of dogs

When your dog is exposed to an allergen, the body releases histamines. This causes localized inflammation and swelling, or hives. Various triggers exist for hives in dogs. The most common causes include:

Insect stings

Notice the individual wheal on this brindle dog’s leg. It’s likely due to an insect bite or sting.

When dogs encounter bees or other biting insects, they have an allergic reaction to the bite. This leads to a raised, red swelling. There may be one or more hives depending on the body’s response.

Most dogs tolerate a single bite or sting without problems, but they may have pain or itching at the site for a few days. As long as the bite/sting wasn’t on your dog’s head or face, and there’s no facial swelling, try to locate and extract the stinger(if it was a bee/wasp sting). Do not squeeze the welt because you may release extra insect venom into the surrounding tissues. If you can’t find the stinger, gently wash the area with a chlorhexidine solution or mild soap. Use a cold compress to soothe inflammation and discourage scratching.

If your dog has a severe allergic reaction, or the head and face are swelling, take him to the vet. The doctor will assess the severity of the condition and administer antihistamines or topical corticosteroids. More aggressive treatment for anaphylactic reactions may include IV medications, fluids, and hospitalization for observation.

Vaccine reaction

Most vaccines are administered under the skin in the neck just behind the shoulders. This is the area where you may find a hive from a vaccine reaction. 

Dogs may have a mild reaction to the antigens found in some vaccines. Signs of an allergic reaction include:

• A small hive or raised, firm lump at the vaccination site (read our article about vaccine lumps)
• Discomfort near the vaccination site
• Low-grade fever
• Decreased appetite
• Lethargy

Most vaccine reactions will resolve in a few weeks. If the lump does not go away or grows larger, contact your vet. Inform your veterinarian if your dog has a history of vaccine reactions before annual health checks.

Treatment is not usually needed, but if it is, your veterinarian will prescribe a non-steroidal anti-inflammatory drug. Immediately head to the clinic if your dog has additional symptoms like

• Vomiting and diarrhea
• Facial swelling
• Multiple hives
• Difficulty breathing

Food allergies

Some dogs develop a sensitivity or allergy to a particular protein such as beef, chicken, or soy. The condition usually appears after your dog has been eating the same brand for several months or years. Signs include:

• Dry, itchy skin
• Hair loss
• Vomiting and diarrhea
• Secondary skin infections

If you suspect your dog has a food allergy, work with your veterinarian to identify the offending allergen and select an appropriate hypoallergenic diet for your furbaby.

Medicines

Pictured below is a dog after reacting to a vitamin K injection. Notice swelling around the eyes and possible bumps under the fur on the foreleg in the background:

If your dog receives treatment for a condition, he may have an acute reaction to the medication. Common drugs that can trigger an outbreak of hives include antibiotics, chemotherapy drugs, and vitamin K. Signs of an allergic reaction include:

• Reddened skin
• Rash with hives usually starts around the head but may spread to other parts of the body
• Extreme itching
• Watery eyes and runny nose

If your dog reacts to medication, inform your veterinarian immediately and cease administering the drug. Your veterinarian will prescribe an alternative medicine for the original condition. He may also administer antihistamines or a topical anti-inflammatory drug to treat the rash/hives.

Other allergies

Your dog may also suffer from environmental allergens like pollen, grass seeds, or molds or from contact allergies to cleaning products, insecticides, or grooming products. Likely symptoms include:

• Red skin/rash
• Hives may start at the point of contact and spread to other parts of the body
• Extreme itching
• Licking or chewing paws
• Intermittent ear infections

As with food allergies, the first thing you should do if your pooch reacts to contact or environmental allergens is to identify and remove or avoid the trigger if possible. For environmental allergies, wipe your dog’s paws and skin every time he comes in from outside, and bathe him once or twice a week to remove allergens from the coat.

For chronic skin allergies and hives, your goal is management. Treatment options include:

• Immunomodulating drugs
• Antigen shots or oral drops
• Steroids or another anti-itch drug

Contact with toxic plants

Dogs can suffer rashes when they contact plants like stinging nettle or poison ivy. When the chemicals or tiny needles irritate your dog’s skin, he may break into a rash and hives. Usually, the reaction is localized to the point of contact. Signs include;

• Reddened skin with a rash
• Local hives
• Itchy or painful skin
• Licking or chewing at the paws
• Pawing at the mouth
• Drooling if the face is affected
• Vomiting and diarrhea

When your dog contacts plants that release irritating oils like poison ivy, bathe him with warm water and a mild shampoo to remove the oils. Handle your dog with gloves to avoid getting the oil on your skin. Dogs that encounter stinging nettle can also be treated by gently washing the affected areas of skin. You may need to scrape the skin lightly to remove the stinging plant hairs. Consult with your vet about giving your furbaby Benadryl or applying a topical ointment to soothe itching/irritation.

How to treat dogs with hives

Many times, hives will resolve in a matter of hours. As long as your pooch doesn’t have facial swelling or difficulty breathing. When your dog breaks out with hives, you can apply cold compresses or give him a cool bath to soothe his skin. Contact your veterinarian before applying any home remedies or giving your dog antihistamines like Benadryl. 

If your dog’s reaction persists or is more pronounced, take him to your veterinarian. Depending on the severity of your dog’s hives, the doctor may administer injectable antihistamines or a corticosteroid.

How to distinguish hives from other skin conditions

Some skin infections look very similar to hives, so you need to know how to distinguish the conditions. Characteristics that can help you identify hives include”

• The lesions arise suddenly, usually due to an allergic reaction.
• They’re red and itchy.
• Hives come in clusters; they’re rarely isolated.
• Hive reactions tend to be localized.
• Hives usually retain hair/fur.

When you take your dog to the vet, he’ll ask you about your pooch’s recent history and examine the hives. Based on the signs, whether your dog was recently exposed to an allergen, and how he responds to treatment, the doctor will confirm the diagnosis of hives.

When to seek veterinary attention for hives

While hives often resolve on their own, it’s advisable to talk to your vet whenever you notice something unusual about your dog’s skin. The doctor may advise you to treat your pooch at home. Seek veterinary attention immediately if:

• Your dog’s face swells
• Your dog has difficulty breathing
• The raised, red bumps persist for more than several hours or reoccur
• The hives don’t respond to home remedies/treatment
• Your dog has vomiting/diarrhea
• Your dog seems weak/lethargic
• Your dog’s gums are pale

Treatment options and likely costs

The type of treatment your veterinarian will use depends on the severity of your dog’s reaction/hives. Options include:

• Antihistamines – this is the most common treatment
• Corticosteroids – if there’s no response to antihistamines or the allergic reaction is more severe
• Epinephrine – if your dog is having an anaphylactic reaction that affects his ability to breathe

Generally, the cost of a veterinary exam and treatment for hives will be around $200. If the reaction is chronic or more severe, the cost may be higher.

Would a vet be able to help over a video call?

Unless your dog is showing signs of anaphylaxis like difficulty breathing, pale gums, and swelling of the face, a video call can be a helpful and affordable first step. The vet can collect information about your dog’s symptoms and any potential contact with insects, plants, or other triggers. For mild, acute cases, the doctor may be able to advise you about at-home treatment.

However, if the hives are a recurring or persistent problem, a video call may not be sufficient. Your dog may require allergy testing or skin culture to make sure there’s no infection. 

Frequently asked questions

Are hives in dogs contagious to other pets or humans?

Hives are usually caused by an allergic reaction, which is not contagious. One exception is if your dog contacts a plant with toxic oils such as poison ivy. In this case, the oils can transfer to another pet or you if you touch the affected areas.

Are there any over-the-counter medications I can use to treat my dog’s hives?

For mild cases of hives, you can use an over-the-counter antihistamine like Benadryl. Always consult with your veterinarian before treating your dog at home. The doctor can advise you on proper dosing and any risks for your pooch.

How long does it take for hives to resolve?

Hives usually resolve in a matter of hours or a few days. If they persist or come back, it’s best to talk to your veterinarian.

Can hives be a sign of a serious underlying health condition?

Hives in dogs occur due to an allergic reaction. They usually resolve on their own, but if there are severe or recurring symptoms, you should treat them as an emergency. Many times, a dog’s reaction to a trigger becomes more severe with repeated exposure.

Are certain dog breeds more prone to hives?

Outdoor dogs tend to be more prone to developing hives because they’re more likely to be exposed to triggers. Other breeds that can be predisposed to allergies/hives include French and English Bulldogs.