How to Tell if Your Dog Has a Fever? Eight Signs Explained.

. 6 min read

While your dog can’t tell you if he or she isn’t feeling well, it is important to know the signs and symptoms of common illnesses in your pet. Dogs’ bodies are very different from our own. They have a higher ‘normal’ body temperature than humans. While 98.6 Fahrenheit is the average body temperature for a human, your dog’s body temperature should be between 101 and 102.5 degrees Fahrenheit. A dog is considered to have a fever when its body temperature is over 103 degrees. A fever of 106 degrees is dangerous or even deadly for a dog.

How do you know if you dog has a fever?

Since your dog can’t tell you they have a fever, you’ll have to look for some warning signs and symptoms. These include:

  1. Lethargy
  2. Is your pet tired and seems to have lost his spunk? Taking naps when he’s usually begging you to throw his favorite ball? While lethargy doesn’t automatically mean your pet has a fever if you notice this symptom you want to make sure you get to the root cause. Lethargy is just one potential symptom of a feverish pet but can also be a symptom of another illness or medical condition. If your pet is lethargic for long periods of time and doesn’t seem to be getting his energy back you’ll want to consult your vet.

  3. Red eyes
  4. If your pet has redness in his eyes along with other symptoms listed here it could be due to a fever. Even if your dog does not have a fever, you may want to get him checked out as the redness could be caused by irritation, infection, allergies, pink-eye or influenza/distemper. You want to make sure to treat your pet accordingly and you’ll need a doctor to diagnose the cause of the redness.

  5. Shivering
  6. If your dog is shivering and it is not because they are cold it could actually be caused by a fever. Make sure your pet is warm and dry if they are shivering. If the shivers are from a fever make sure you are not making them too hot.

  7. Warm, dry nose
  8. Some people say that you can tell if a dog is sick just by feeling their noses. While this is not completely true, a warm, dry nose could indicate that your dog has a fever, especially if it is coupled with some of the other symptoms outlined here.

  9. Nasal Discharge
  10. Nasal discharge is another symptom that can be caused by a fever. This is not the only reason your pet may have nasal discharge. Other reasons could include allergies irritation, kennel cough or a more serious illness like cancer. If your dog has nasal discharge you’ll want to work with your vet to determine the cause and provide appropriate treatment.

  11. Coughing
  12. If your dog is coughing it could be a case of kennel cough, a highly contagious illness that is caused by a mix of viruses and bacteria. It is called kennel cough because it can spread quickly to dogs who come in contact with it in a kennel, doggie daycare or even from a visit to the groomer if a sick dog was seen in the salon. There is a vaccine for kennel cough and if your pet is a frequent visitor at doggie daycare or regularly socializes with other dogs you may want to discuss the vaccine with your vet. Some boarding facilities or groomers require all dogs to be up to date with this particular vaccine.

  13. Vomiting
  14. Your pet’s fever may be accompanied by vomiting. This could be caused by a virus or because your pet ingested something that is making them sick. If your pet is vomiting you’ll also want to check for a fever and work with your vet to determine what is causing the vomiting. Bowel obstructions like from eating a toy or other non food item can also cause vomiting and fevers and may require surgery to remove the obstruction. You will also want to work with your pet’s medical care team to ensure that your pet is adequately hydrated and getting nutrition if they have been vomiting. In some cases your dog might need an IV for fluids.

  15. Loss of Appetite
  16. Fevers can also be accompanied by a loss of appetite. If your food motivated dog is suddenly turning up his nose at his favorite treats this could be a cause for concern. Like other symptoms listed here, this alone does not mean your pet has a fever but could be another sign. Loss of appetite could signal pain in your pet’s mouth (toothaches) or somewhere else in their bodies. If your pet isn’t eating and/or drinking as normal you’ll want to take them to the vet for an exam to determine why they don’t have an appetite. While a fever due to illness may make your dog not feel very hungry you’ll want to be sure you’ve ruled out other more serious reasons and worked with your vet on a treatment plan. You might need to temporarily modify your dog’s diet. Soft foods or bland food may be very helpful but ask your vet for guidance.

The most accurate way to determine if your pet has a fever is to take your dog’s temperature. For the most precise temperature, you’ll want to use a rectal thermometer. This may not be easy or even comfortable for you to do and you may want the assistance of an experienced vet tech. You can also use an appropriately designed thermometer to take your pet’s temperature in their ear. While this may be more comfortable and easier for you to get a reading, it can be slightly less accurate.

Note that there are now digital thermometers that may make this task easier. If you’re having trouble getting a temperature reading you can also try under your pet’s armpit. The armpit is less accurate than a rectal or ear temperature but can still give you some information before you get to the vet.

One more word of caution, most thermometers that are not digital contain mercury inside a glass tube. You want to make sure not to let your pet bite or break the thermometer. While broken glass on its poses some hazards like putting you both at risk for cuts and scrapes, the mercury is also toxic to both pets and humans and needs to be cleaned up and disposed of properly.

What causes dogs to get fevers?

Since many of the symptoms of fevers have many causes, what causes the fever itself? There are many common reasons why your pet’s temperature may be elevated. Your vet will run diagnostic tests to determine the reason for your pet’s fever. These tests may include a physical exam including looking in your dog’s ears and feeling his belly, bloodwork and X-rays or an ultrasound. Your vet will be looking for:

  • Infections
  • An infection can cause a fever in your dog. Common infections that your vet will be looking for are:

    • Urinary Tract Infection (UTI)
    • Ear Infection
    • Wounds or cuts that get infected
    • Infection of internal organs including the liver or kidneys

    Most of these infections can be treated easily with antibiotics that your vet will prescribe.

  • Inflammation
  • Inflammation can also cause your dog’s temperature to rise. To treat this your vet will want to determine the cause of the inflammation to treat it properly. This may involve testing your pet for autoimmune disease.

  • Tick-borne illness
  • Ticks can cause Lyme Disease and other illnesses in dogs. If your dog is running a fever and you’ve removed a tick recently or been in a tick-infested area you must let the doctor know. Pro tip: If you remove a tick from your dog, take a photo before you destroy it. This will help your vet identify the specific type of tick and the diseases it carries.

  • Ingesting a toxic or poisonous substance
  • If your dog eats something toxic or poisonous he can get a fever as the toxins spread through his system. You’ll want to retrace your steps (and your dog’s) to see if he has come in contact with: rat poison, antifreeze or a plant or flower that is poisonous to dogs.

  • Vaccines
  • In some cases, your dog may have a low-grade fever after receiving a vaccine. This should resolve itself in 24 -48 hours but you’ll want to carefully monitor your pet to make sure the fever breaks.

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How to treat your dog’s fever

  • To help lower your dog's temperature you can soak some a few pieces of cloth in cool water and place them around your pet’s paws and ears.
  • You may also want to try to get your pet to drink some fresh, cool water.
  • You should never give your pet human fever reducers like Tylenol or acetaminophen as these are toxic to them.
  • When your pet is under the weather, it might be a good idea to give them a quiet space to rest and recover. If you have multiple pets it could even be a good idea to isolate them from the other animals in your house. This is especially important if they are contagious. You don’t one sick pet turning into two.
  • If your pet does have a fever you want to monitor them closely until it breaks. Make sure their fever does not return. Be sure to seek medical care and appropriate treatment for the cause of your dog’s fever as needed. You can never be too careful.