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How to Tell if a Dog Has a Fever? Vet-Reviewed Causes & What to Do


Jun 10, 2023
medical treatment of sick husky dog in vet clinic


medical treatment of sick husky dog in vet clinic
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It’s heartbreaking to watch your pet endure a fever. Like humans, dogs experience a fever when their body temperature is higher than normal. A healthy dog should have a temperature of around 101–102.5°F, whereas a fevered dog may experience temperature fluctuations beyond the norm.

In this article, we will review the signs of fever and some potential causes in dogs. We will also discuss how to take your dog’s temperature and soothe your poor pup. To learn more about caring for your fevered dog, keep reading below.


Signs of Fever

Other than an abnormal body temperature, several signs may indicate that your dog is suffering from a fever. Some of the most common signs include:

  • Lethargy or weakness
  • Redness of the eyes
  • Warm ears and a warm, dry nose
  • Lack of appetite
  • Coughing
  • Vomiting
  • Shivering

It can be difficult to notice a fever in dogs because their body temperatures can change from emotional excitement. Therefore, looking for these other signs is critical when trying to detect a fever. However, the best way to confirm whether or not your dog has a fever (as well as why he has one) is to take him to the vet.

vet examining a sick German Shepherd dog
Image Credit: Roger costa morera, Shutterstock

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The 8 Causes of Fever

There are several reasons why your dog may have a fever, and not all of them are clear-cut. But for the most part, canine fevers fall into one of these categories: inflammation, infection, immune-mediated, and cancer-related. Sometimes, the cause of a fever may be impossible to determine.

1. Vaccinations

Vaccinations are essential to your dog’s well-being, as they boost his immunity against diseases that may threaten his health. While they are vital to your dog’s long-term health, they can cause some minor, short-term side effects. A fever is among them since anything that activates the immune system has the potential to lead to a fever.

Other side effects may include:

  • Mild redness and swelling of the injection site
  • Fatigue
  • Decrease in appetite
  • Nasal discharge or sneezing
  • Coughing

The fever from vaccinations tends to be inconsequential and short and rarely ever requires veterinary treatment. Still, if your dog appears highly uncomfortable or the side effects last longer than 24 hours, reach out to your vet.

2. Ear Infection

pug dog's ear affected by an ear mite
Image Credit: Glikiri, Shutterstock

Dogs are especially prone to ear infections due to the shape of ear canals, and it is estimated that around 20% of dogs have some form of ear condition. Some of the first indications of an ear infection include whining, scratching at the ears, and head shaking. As the condition progresses, you may notice other signs, such as:

  • Red and swollen ear canal
  • Dark discharge from the ear
  • Odor emanating from the ear
  • Pain and itchiness
  • Crusting or scabs inside of the ear

Many factors may predispose your dog to an ear infection, so take him to the vet to determine the cause and how to treat it. Ear infections cannot be treated at home, and the infection may spread without prompt action.

3. Urinary Tract Infection (UTI)

Urinary tract infections (UTIs) are common in dogs. If your dog breaks house training rules (such as going potty indoors), that can be a sign that something is amiss.

Other signs of a UTI include:

  • Excessive urination
  • Straining to urinate
  • Whining when urinating
  • Blood in urine
  • Frequent licking of the genitals
  • Urine with a strong odor

If you believe your dog has a UTI, contact your vet immediately. Bladder stones can develop alongside a UTI, leading to more health concerns. The sooner you can get treatment for your dog, the better.

4. Bacterial, Fungal, or Viral Infections

Infections of all sorts can lead to fever in your dog. Whether the infection is bacterial, fungal, or viral, it can stimulate an immune response and lead to a fever. Signs of infection may vary depending on the specific infection, but you can expect to see lethargy, sneezing, coughing, or other respiratory problems.

You must get a vet’s diagnosis and treatment to care for your dog, but the treatment will vary depending on the cause of the infection.

dalmatian dog looking sick
Image Credit: Alexander Hagseth, Shutterstock

5. Pancreatitis

Pancreatitis is the inflammation of the pancreas, which is responsible for creating digestive enzymes used to break down food. This inflammation is due to an early activation of the digestive enzymes, causing the pancreas to digest itself. There are two versions of pancreatitis: acute pancreatitis and chronic pancreatitis.

Signs of acute pancreatitis include:

  • Extreme exhaustion
  • Frequent vomiting
  • Dehydration
  • Abdominal pain
  • Collapse
  • Shock

Chronic pancreatitis is not as common and displays less intense signs. Signs of chronic pancreatitis include:

  • Lethargy
  • Decreased appetite or refusal to eat
  • Abdominal pain
  • Vomiting

Pancreatitis can be caused by exposure to high-fat meals or garbage consumption, but the cause is often unknown. Still, you will need to take your dog to the vet to receive a proper diagnosis and treatment plan.

6. Sepsis

Sepsis occurs when the body is reacting to an infection. It is an extreme reaction that can lead to inflammation throughout the entire body and even cause organs to shut down. This condition can quickly become life-threatening.

Signs of sepsis include:

  • Lethargy
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Disorientation or confusion
  • Rapid heart rate or breathing
  • Low blood pressure

If you suspect that your dog has sepsis, contact your vet immediately; it is a medical emergency.

dog not eating its food
Image Credit: Daria Lixovetckay, Shutterstock

7. Autoimmune Diseases

Autoimmune diseases are closely linked to the immune system, and a flare-up may lead to a fever. Autoimmune diseases prevent your dog’s immune system from distinguishing between foreign bodies and the regular, healthy cells within your dog’s body. This leads the immune system to attack itself, causing damage to the body.

The reason behind autoimmune diseases is unknown. Some believe that genetics or environment may play a role, but that has not been confirmed. Several autoimmune disorders attack different areas of your dog’s body, and if you notice your dog displaying troubling signs, take him to the vet to see if an autoimmune condition could be the culprit.

8. Ingestion of Toxins

Dogs seem to love to get into things they shouldn’t. At best, this causes a minor tummy ache. At worst, it can lead to a toxic reaction. There are several things dogs should never eat, including alcohol, chocolate, and onions. If your dog is experiencing a fever after eating something he shouldn’t have, immediately reach out to your vet or local emergency clinic. If possible, bring the label of the ingested item with you so that your vet can evaluate the severity of the problem.

a border collie dog looking sick covered with blanket on couch
Image Credit: Lindsay Helms, Shutterstock

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How to Soothe Your Dog’s Fever

To help your dog battle a fever, you can take a soaked cloth and apply cool water around his ears and paws. You can also have your dog wear a canine cooling vest to lower his temperature. When his temperature dips below 103°F, you can stop applying water.

How to Take Your Dog’s Temperature

Taking your dog’s body temperature is the best way to detect a fever. Only two instruments can accurately confirm your dog’s internal temperature: an ear thermometer or a rectal thermometer.

Ear thermometers are the least invasive (and probably less daunting) of the two options. You will gently insert the stick into your dog’s horizontal ear canal for ear thermometers. It should take around 60 seconds to collect an accurate temperature reading.

Rectal thermometers are just as accurate as ear thermometers, though many people may find them less appealing for obvious reasons. If you use a rectal thermometer, lubricate it with baby oil or petroleum jelly. Wait around 60 seconds for an accurate reading.

No matter which thermometer you choose to use, make sure that you follow the instructions carefully.

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When to Take Your Dog to the Vet

When your dog’s temperature hits 103°F or higher, take him to the vet. Temperatures over 106°F can damage his organs, leading to fatal consequences. It is better to go early and be safe rather than sorry.



No one likes to see their dog suffer from a fever. Regardless of the cause of the fever, watching our pets endure sickness is a difficult matter. We hope this article has helped you spot the signs of fever and learn more about the potential causes. If you believe your dog is battling a fever, do not delay getting him the veterinary treatment he needs. The sooner he is healed, the sooner he can return to his tail-wagging self!

Featured Image Credit: Pressmaster, Shutterstock

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