Fevers in Dogs and Cats

Ask PHP Pete!

Dear PHP Pete,

How can I tell if my dog or cat has a fever? Are there signs/symptoms? What should I do if my pet has a fever?


Hot Under the Collar

Fevers in dogs and catsDear Hot Under the Collar,

The normal body temperature range for a cat or dog is approximately 100-103°F. Temperatures above 103°F might be either a true fever or hyperthermia.

Hyperthermia occurs in situations such as:

  • Overheating
  • Strenuous activity
  • Increased anxiety (such as a visit to a veterinarian’s office)
  • An underlying medical condition

Hyperthermic animals sense that they are over-heated. They may pant, have bright pink gums, or become agitated or distressed. They may also exhibit cold-seeking behaviors.

During a true fever, the animal’s internal “thermostat” (set by the hypothalamus in the brain) has been reset to a higher temperature. This makes the animal feel cold. As a result, he or she may exhibit symptoms such as:

  • Shivering
  • Huddling
  • Having goosebumps
  • Seeking heat
  • Undergoing behavioral changes such as lethargy, depression, or reduced appetite
Causes of Fevers Examples Include…
Infections Viral, bacterial, fungal, or caused by other microorganisms. Bite wounds, tick bites, and communicable diseases are a few possible sources of infection
Inflammation (non-infectious) Inflammatory bowel disease, pancreatitis
Immune disorders Polyarthritis, systemic lupus erythematosus
Neoplastic (cancer) Lymphoma, leukemia
Drugs Tetracycline, cephalosporins, penicillins

Taking Your Pet’s Temperature

  1. Apply a lubricant (such as petroleum jelly or baby oil) to the tip of a digital rectal thermometer
  2. Gently insert about 1 inch into the rectum
  3. Push the button, and wait for the beep

If the temperature is above 103⁰F you should see your veterinarian. A temperature of 106⁰F or above may be life-threatening and requires immediate assistance.

Diagnosing a Fever

Your veterinarian may use a variety of methods to determine the underlying cause of a dog or cat’s fever. A physical examination includes listening to the heart and lungs, as well as feeling along the body for areas of pain or swelling. Scans or tests may also be conducted, such as:

  • Bloodwork
  • Cultures
  • Urinalysis
  • Ultrasound

Determining a Treatment

The signs and symptoms accompanying a fever may point to its source. For example, coughing or wheezing may indicate an upper respiratory infection. Identifying the underlying reasons for the fever will allow the veterinarian to decide on potential treatment options, which may involve:

  • Fluids for dehydration
  • Antibiotics (bacterial infections)/ antifungals (fungal infections)
  • Immunomodulating drugs
  • Cancer drugs

Never give human fever medications to a dog or cat. Examples include acetaminophen, ibuprofen, or aspirin. They can be toxic or even deadly!


Remember, fevers are not always caused by bacterial infections – antibiotics will not be effective against fevers with non-bacterial causes. A veterinarian will determine the best course of action for your pet.

Yours Truly, PHP Pete