Fever in Dogs

Fever refers to an abnormally high body temperature. The normal body temperature in dogs is between 101 and 102.5º Fahrenheit (38.3-39.2º Celsius). Temperatures at 103ºF (39.4ºC) or above are considered a fever. High body temperature can be caused by infection, environmental heat, or excessive exercise. A body temperature of 106ºF (41.1ºC) or above can be life-threatening and should be treated as a medical emergency. Pyrexia is more commonly known as fever, and may be mild, like what is seen at the onset of a viral infection (i.e. human cold), or severe, causing seizures or organ shut down.

Although your pet can have a fever with no symptoms, some symptoms are often present with a fever, including:

• Lethargy
• Shivering
• Loss of appetite
• Rapid heart rate
• Dehydration
• Panting
• Vomiting
• Coughing
• Nasal Discharge

Causes of high temperature in dogs can include:

• Infection – The body is designed to increase in temperature when infection is present. Many bacteria, viruses and fungi are heat sensitive and cannot survive at the higher body temperature.
• Inflammation/allergic response – Fever can be associated with these.
• Toxins – Consuming certain poisonous materials may result in fever.
• Medication – Some medications may elevate body temperature
• Vaccination – As with infection, the body’s immune system will often respond to vaccination with a low grade fever. This fever may last up to 48 hours after vaccination.
• Severe anxiety - The panting and pacing associated with anxiety can cause a slight fever.
• Fever of Unknown Origin – Sometimes the cause of fever cannot be determined. This is often the case with immune system abnormalities, blood and bone marrow disorders and cancer.

In order to determine your pet’s body temperature, you will need a thermometer. Digital thermometers that are specifically designed for rectal use are available at most pet stores. Human thermometers are not designed to measure the higher body temperature of dogs and are not as accurate.

To take the rectal temperature, rub a bit of baby oil, vegetable oil or petroleum jelly on the end for lubricant. Gently insert the thermometer one inch into the anus. Wait for the thermometer to signal it is finished reading.

The veterinarian will need a history of the pet’s symptoms, any medications, recent events and any allergies. A physical examination will look for swollen lymph nodes, abdominal swelling, pain in the joints, and other signs of infection or systemic abnormalities.

Laboratory diagnostics that can be useful in determining the cause of fever include a complete blood cell count, biochemistry profile and urinalysis. These tests examine the function of the metabolic and endocrine systems and can indicate infections or other causes of elevate body temperature.

Radiographs can identify abnormalities in organ systems, cancer, or infections (i.e. a visible abscess).

If your pet has a fever greater than 103ºF (39.4ºC) you will need to have a veterinarian examine him. A body temperature at or above 106ºF (41.1ºC) should be considered a medical emergency.

You can help bring your pet's temperature down by wiping his paw pads and ears with a cool wet washcloth. You may also wrap ice packs in a towel and place it against his chest and abdomen. A fan to supply cool air is useful as well.

Never treat your dog with human medicines without the instruction of a veterinarian. Aspirin and acetaminophen are toxic to dogs at certain levels.

Your veterinarian will use the information gathered from the pet’s history, physical examination and diagnostic tests to decide the course of treatment. Intravenous fluids will aid in hydration and electrolyte balance. Antibiotics are prescribed to treat infection. In some cases, additional medications and/or surgery may be required to treat the underlying condition.

Be sure to monitor your pet’s temperature at home and report any increase in body temperature or failure of the pet to respond to treatment to your veterinarian. Follow the instructions for treatment and medication administration carefully. Be sure your pet is getting adequate water, food and rest. If possible, keep your pet separate from children and other pets while he rests and recovers.

Never treat fever with human drugs unless directed by your veterinarian. Home treatment for fever can worsen the condition or lead to life-threatening conditions.