Pyrexia in Dogs: Symptoms, Causes and Treatments for Dog Fever

If you’ve ever reached out to pet your pup and felt they’re really warm, you would naturally get concerned. Dogs have a higher body temperature than us humans. In dogs, normal core (rectal) temperature is approximately 101 -102.5 degrees Fahrenheit (38.0 -39.0 degrees Celsius), though some normal fluctuations outside this range is very likely during the day.

However, where you need to be careful is when they feel warmer than usual. Core body temperature may become elevated due to pyrexia, the medical term for fever. More often than not, your pooch’s core temperature is normal, but there may be times when they can run the risk of running up a fever. Here’s how you can detect and spot the signs of pyrexia in your dog. Generally speaking a reading of anything higher than 101.5°F in your dog can be regarded as fever.


The best way to check the core temperature on your pup is rectally, using a digital thermometer (like the Care Touch thermometer I have and recommend).

Pyrexia Symptoms in Dogs

According to PETMD, here’s a quick checklist of the signs of pyrexia in dogs.

  • High core (rectal) temperature
  • Increased rate of breathing
  • Shock
  • Weakness
  • decrease in appetite
  • Rapid heart rate
  • Shivering
  • Dehydration
  • And more.

What Causes Dog Fever?

The most pertinent question that all pet parents have is what caused pyrexia in your dog, so treatment can begin? Finding the culprit behind your dog’s increased temperature may be a little harder to detect. There are so many variables that could have contributed to an elevated body temperature.

The first logical assumption that caused a spike in your pet’s temperature is some sort of a virus or infection. Fever is your body’s way of fighting off infection by making the conditions less suitable for viruses and bacteria to survive. Evidence suggests that during a fever certain type of immune cells work better at fighting off a virus. So in this instance, a fever is the body’s response to an infection and not an infection itself.

Alternative causes for setting off a fever in your dog include:

  • Metabolic diseases such as intoxication, kidney disease or diabetic ketaocidosis
  • Immune-mediated haematological disease
  • Cardiac disease
  • Respiratory disease
  • Fluid in/around lungs
  • Tumors
  • Various drugs' side effects
  • Bacterial endotoxins
  • Fear
  • Anxiety
  • Hypertension
  • Obesity
  • Pneumonia
  • Pulmonary disease
  • Edema
  • Tracheal collapse
  • Hyperthyroidism
  • Fever of undetermined origin
  • And more.

Watch Sam Meisler DVM, a small animal veterinarian discussing what sets off fever in dogs, a very informative and brief video that is worth watching.

Treating Pyrexia in Dogs

There is little that can be done for a dog at home with a running fever other than keeping them as comfortable as possible. Ensuring they are in a cool spot, have access to fresh water and letting them rest is an important first step. If at any point in time, your dog gets agitated and there are marked elevations in core body temperature– bring them straight away to your vet. Treatment of pyrexia in animals needs to be aimed first at identifying and addressing the underlying cause.

Cooling off your pet may work at reducing your pet’s temperature in the short term, but this can also trigger the thermoregulatory center to stimulate heat production and conservation further which is counterproductive.

Your vet will be able to properly diagnose your pet’s fever by running:

  • A thorough physical exam (the vet will ask if they’ve been travelling, come in contact with bugs, history medical background, etc.)
  • Draw blood and run a complete blood count
  • Take a fecal and urine sample to check for parasites/worms and the bladder for infections.
  • Rule out all other possibilities by taking an MRI, CT or ultrasound scan.
  • Endoscopy and more.

If a definitive diagnosis is obtained, a specific treatment can be initiated. Treatment options include:

  • A course of antibiotics and fluid therapy being the most common
  • Removing the infection with surgery in some cases
  • Other medications.

Final Word

Properly diagnosing and finding the culprit behind your pet’s spike in core body temperature is imperative and can be a lengthy and expensive process. The problem arises if the vet cannot arrive at a definitive diagnosis. It’s important to find a good and reliable vet that you can trust to work with you. Your beloved pet’s health is important!

References and Further Reading:

Saunders Solutions in Veterinary Practice: Small Animal Emergency Medicine, By Shailen Jasani

Canine and Feline Infectious Diseases, by Jane E. Sykes.

"Elevated Body Temperature Helps Certain Types of Immune Cells to work better, evidence suggests", Science Daily.

"Fever in Dogs",

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