Can Dogs Get Hives from Heat?

Have you ever had a case of the hives? Itchy, raised bumps that are localized and swollen are the typical signs. One of the worst parts about hives is you may never know why you have these miserable, itchy bumps all over your skin. Sometimes, all that you can do is try to chase the misery away with medication and wait them out. There is really nothing funny about getting hives. Have you wondered if your dog can get hives, too? Can your dog get hives from the heat?

Can Dogs Get Hives from Heat?

YES!

Typically,  dogs develop hives because they are allergic to something they ingested or inhaled, but sometimes the cause can be even trickier!

While it is quite rare, your dog can get those red, itchy bumps for no more reason than getting too hot and sweaty. You might suspect this condition if all other causes for hives have been ruled out, such as allergies to substances that are new in your dog’s diet, or any new vaccinations or medications they have had recently.

If you have had an unusually hot day, there is the possibility that your dog might be reacting to the heat or the sun and that these could be the cause of your dog’s hives. Your veterinarian can help you rule out possible causes and help you zero in on what might be causing their itchy skin. Hives are not contagious, are often harmless, and will go away on their own (with a bit of help from mom or dad in staying comfortable until they do).

Does My Dog Have Hives from Heat?

The symptoms of hives from heat are generally the same as hives caused by any other condition. A lack of appetite, fever and lethargy may precede the hives attack. Raised bumps may appear on the skin, face, ears or tongue. The bumps may be obvious, particularly in shorthaired dogs, because the hair may stand up and look rippled.  Your dog will most likely not be able to stop itching. It is also possible that your dog’s face may swell up and they may have difficulty breathing-- these are considered acute symptoms and may need treatment by a vet. 

Hives caused by heat are thought to be the result of a dog’s sweat glands releasing sweat and acetylcholine. The acetylcholine reacts with mast cells, which in turn cause the hives. Hives can also be caused by a number of other conditions such as: 

• Food items
• Household chemicals
• Medicines
• Vaccines
• Certain plants (such as nettles)
• Inhaled allergens
• Milk retention (during female’s heat cycle)

It is important to check for allergens and other causes before assuming that your dog has hives from heat or the sun, which is quite rare. In most cases, hives are harmless, if miserable, and will go away in a few days. If acute symptoms accompany hives, such as swelling of the throat or difficulty in breathing, you should take your dog to a vet right away.  You should also take them to the vet if the hives do not go away in a few days. To learn more about the symptoms and causes of hives, please check out our guide on hives.

How Do I Treat My Dog’s Hives?

The treatment of hives involves an antihistamine such as Benadryl to stop the histamines causing the hives, and topical remedies that can help to relieve the itching.  Talk to your vet to find out what an appropriate dose of Benadryl would be for your dog. 

Your dog will greatly appreciate an oatmeal bath or being bathed in green tea to help soothe the itch. Chamomile can also help calm the intense itching--simply make a batch of chamomile tea and pour the cooled liquid over your poor dog’s inflamed skin. 

Prevent hives from reoccurring by keeping your dog out of the sun and heat for long periods of time. While your dog might miss their outdoor playtime, they will be much happier without the unwelcome red bumps that make fleas seem like a few friendly hitchhikers. Most often hives caused by heat will disappear as quickly as they appeared. And, chances are good that you will never see them again.

How are Hives Similar in Dogs and Humans?

Hives are a symptom of an allergic reaction and can occur in humans and most any other animal. The common symptoms you are likely to see are:

• Red, raised bumps
• Swelling of the face, eyes and neck (in acute cases)
• Intense itching
• Difficulty breathing (also in acute cases)

How are Hives Different in Dogs and Humans?

For the most part, you will not see any differences in hives between dogs and humans, and like dogs, humans can get heat related hives. The few differences you might see are:

• The bumps may be more noticeable in humans since we are not all covered in hair like our furry friends. With dogs, frequently your first clue there is a problem is that they cannot stop scratching

• Dog's faces often swell up like balloons and while those puffy jowls might look cute, they can be a common sign that your dog is reacting to something.

Case Study

A normal healthy, happy Pitbull spent his afternoon in the backyard on a hot summer day. While normally he loves being outside in the sun, he comes back inside and looks lethargic, his hair is all rippled and standing on end, and he cannot stop scratching. On closer inspection, the dog’s owner discovers raised, red bumps that seem to be the culprit of their poor dog’s misery. The owner recognizes the hives for what they are and calls the vet, unsure what to do. The vet offers some advice on how to soothe the itching topically with an oatmeal bath and, after checking his patient’s weight, gives the owner the correct dosage of Benadryl to give to the dog. The next day, the normally bouncy happy puppy is up to his old antics again.