What causes fever in dogs? (6 signs & symptoms you should know)

Wondering what causes fever in dogs? Learn how to tell if a dog has fever, what signs to look for, and how to take your dog's rectal temperature. Start reading!
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Like humans, dogs do get fevers. Fever in dogs is generally not an illness but a sign that the dog’s immune system is fighting an infection, or it’s a symptom of a disease. 

In this article, I will discuss the different causes of fever in dogs, along with their symptoms, how to take your dog’s rectal temperature, as well as other things you need to know about dog fever.

What Causes Fever in Dogs?

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Fever in dogs can be caused by a number of different factors. Some of the most common reasons that a dog might have a fever are infections, parasites, bacteria, seizures, vaccinations, and cancer. Depending on the causes of the fever, dogs may also suffer from nausea, vomiting, loss of appetite, and lethargy.

Later in this article, I will look in detail at the different causes of fever in dogs. So, keep reading until the end.

Now let’s answer a simple question that seems obvious but isn’t.

What Is Dog Fever?

The term ‘fever’ is generally used to describe an increase in body temperature due to infection or inflammation. Dog fever is a temperature that is higher than a dog’s standard body temperature, which is 103 degrees Fahrenheit (ca. 39 degrees Celsius). The veterinary word for dog fever is known as pyrexia. 

When compare with human body temperature, dogs have a higher normal body temperature than humans. 

A normal human body temperature is around 97.6 to 99.6 degrees Fahrenheit (ca. 37 degrees Celsius), while a normal dog body temperature is 101 to 102.5 degrees Fahrenheit (ca. 38 degrees Celsius). This explains why fleas are more attracted to your dog than to you.

What Are The Symptoms & Signs of Dog Fever?

What can cause a dog to have a fever - Signs of Dog Fever

Your dog can’t tell you he has a fever but can only give you some common signs and symptoms that indicate he is suffering from fever. 

Knowing these symptoms is a great way to determine when your dog is sick. 

You should keep a careful eye on your dog in case you notice anything out of the norm. 

How to tell if a dog has a fever? The common symptoms of dog fever include the following.

1. Shivering

Just like humans, your dog will shiver when he has a cold, but if your dog’s shivering is not from cold, it could be caused by a fever. 

Make sure your dog is warm and dry if he is shivering. And if the shivering is caused by a fever, make sure you are not making your dog too hot.

It is important to be aware of other symptoms like vomiting, diarrhea, or limping. Then contact your vet immediately.

2. Nasal Discharge

A runny nose is another symptom that your furry pal is suffering from fever. 

Though, fever is not the only reason your dog may have nasal discharge. Other causes can include kennel cough, allergies irritation, or a more serious sickness such as cancer. 

Consult your vet if your dog has nasal discharge to diagnose the cause and provide proper treatment.

3. Vomiting

Your dog’s fever may come with vomiting. This could be caused by a virus or because your dog has ingested something that makes him sick.

A dog with a fever will have a temperature of about 103 degrees Fahrenheit (ca. 39 degrees Celsius) or more. 

If your dog’s fever is related to sickness, vomiting may be one of the symptoms. 

While dogs with a fever may be thirsty, they are often not hungry. You will need to work with your vet to determine the cause of the vomiting.

4. Loss of Appetite

Dog fever can come with the loss of appetite. If your dog suddenly rejects his favorite treats, this can be cause for concern. 

Just like other symptoms mention here, loss of appetite could be a sign of pain in your dog’s mouth or in another part of the dog’s body. 

If your dog refuses to eat or drink, as usual, you should take him to see the vet for an examination and decide the reason for his loss of appetite. 

Though a fever that is due to sickness may make your dog less hungry, you also need to make sure you have ruled out other more serious causes and worked with your vet on a treatment plan.

5. Red Eyes

If your dog has red eyes or excessive discharge from his eyes, this could be due to a fever. While red eyes don’t automatically mean your dog has a fever if you notice this symptom, you may want to get him checked out as the redness could also be a symptom of another illness or medical condition.

6. Coughing

If your dog is coughing fervently, this could be a sign of some kind of infection or inflammation. 

This condition can make the dog’s body temperature increase as the fever tries to fight off harmful bacteria. 

If the cough persists, it is advisable to consult your vet for an appropriate diagnosis and treatment.

What Are The Causes of Dog Fever?

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There are a lot of conditions and illnesses that can cause your dog to develop a fever. 

The following are some of the most common causes of fever in dogs:

1. Infection

Fever is often a response to inflammation or to fight off infection; the body temperature rises to prevent the growth and pathogens reproduction. In dogs, sometimes we can see fever as a symptom of a serious skin infection known as pyoderma or an infected wound from injuries. 

In these situations, prescription antibiotics and anti-inflammatory drugs would be needed to treat the infection. 

2. Bacteria

Bacteria are one of the most common causes of fever in dogs that vet see in daily practice. This could include diseases like canine distemper, parvovirus, leptospirosis, and Lyme disease in pups. 

Dogs with bacteria will often show other symptoms of illness, like runny nose, red or watery eyes, diarrhea, vomiting. 

When any of these symptoms come with a fever, it is best to have your dog examined by a veterinarian immediately to find out what is wrong and to be able to administer the appropriate treatment.

3. Ingesting of Toxic or Poisonous Substance

When a dog ingests something that he shouldn’t, he may develop a fever as the poisons circulating through his system. You will need to check if he has come in contact with substances like antifreeze, rat poison, or flower that are toxic to dogs.

4. Seizures

Another possible cause of fever in dogs is prolonged seizures and muscle tremors. This happens because when the muscles of the body are constantly contracting, they produce an enormous amount of heat. 

In some cases, this can cause severe temperatures of about 106-108 degrees.

Immediate veterinary attention is required in these cases because your dog can die or suffer permanent brain damage in as little as 10 to 15 minutes with such a high body temperature. Your vet can act quickly to treat the seizure.

5. Vaccines

Your dog may develop a mild fever as a side effect of his routine vaccinations. This should resolve within 24 to 48 hours, but you will need to carefully observe your dog make sure the fever subsides. 

If your dog’s fever is a response to its vaccines, make sure he has access to water as well as the cooler parts of the house. 

Monitor your dog’s temperature to be sure it doesn’t get any higher. And if your dog still has a fever above 103 °F after 48 hours, contact your vet.

What Is a Dog’s Normal Temperature?

According to the American Kennel Club (AKC), a temperature between 100 °F and 103 °F degrees (37.5 – 39.5 °C) is normal for dogs. Like humans, a dog’s normal temperature should remain within a certain range. Too high or too low a temperature could indicate something serious, and you should take your dog to the vet. 

Like humans, a dog’s temperature can rise or fall due to various reasons, which include shock, infection, inflammation, vaccinations, or accidentally ingesting something poisonous. 

How Do You Take a Dog’s Rectal Temperature?

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A dog’s temperature is part of his complete physical examination because it plays a very important role in diagnosing disease and evaluating various conditions. 

Whether you have a new puppy or have had your dog for a while, knowing how to take his temperature is important. 

You can take your dog’s temperature with an ear or rectal thermometer. 

The following are the step-by-step guide on how to take your dog’s rectal temperature:

  • Step 1: Clean and lubricate the thermometer, shake it until the temperature is below 94 degrees. If you are using a digital thermometer, wait until the screen shows that it is ready to use.
  • Step 2: The next step is to have someone hold your dog firmly; your furry pal should be in a standing position.
  • Step 3: With a slight twisting motion, carefully insert the thermometer into your dog’s anus. Insert half the length of the thermometer into the dog’s rectum; insert less in small dogs. Be sure to hold the thermometer; don’t allow it to slide down your dog’s anus. Hold it in there for at least two minutes.
  • Step 4: After about two minutes, remove the thermometer, clean it and read the temperature, a temperature of about 100 to 103 degrees Fahrenheit is normal.

What to Do if Your Dog Has a Fever

To help reduce your dog’s fever, first put cold water around your dog’s paws and ears with a damp towel or cloth. 

Keep monitoring your dog’s temperature; you can stop applying the water when the temperature drops below 103 degrees Fahrenheit. 

See if you can convince your dog to drink some water. 

Keep monitoring your dog closely, to make sure the fever does not return, consider taking him to the vet if he develops other symptoms.


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Dogs with fever may have various symptoms, depending on the cause of the fever. The most common symptoms are decreased activity, shivering, nasal discharge, fatigue, depression, and loss of appetite. The dog may also seem restless and uncomfortable. 

Some dogs may pant, have excessive saliva, increased heart rate, and show signs of discomfort like scratching, whining, or a change in normal behavior.

As you can see, detecting the cause of fever in dogs is usually a simple process. If your furry pal has a fever, make him drink small amounts of water consistently to remain hydrated; however, don’t constrain him to drink it. 

And don’t give your dog any human medication intended to lower a fever. 

If you’re concerned about your dog’s temperature, always check with your local vet to find out whether your dog has a fever.

Thank you for reading and have a great day!

Until next time!

A big hug.

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Housam Ayouni
Housam Ayouni

I am a professional in the field of canine behavior and care with many years of experience. Through my dog blog, which has reached over one million dog owners, I offer practical tips and guidance to support dog owners in creating strong, positive relationships with their pets and promoting the well-being and happiness of all dogs. My goal is to help dog owners create a harmonious and fulfilling life with their furry companions.

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