Why Does My Dog Have a Fever? Causes and Care Strategies

Just like people, dogs have an optimal body temperature range, and temperatures over this range suggest they’ve got a fever. There are a variety of reasons why your dog might have a fever – including infection, disease, and injury. In this article for PETsmarts we’ll teach you how to take your dog’s temperature, let you know how to tell if you’re dog has a fever and give our tips on how to treat a fever.

Can Dogs Get Fevers?

Dogs can absolutely get fevers – and just like with people, fevers are a symptom rather than a cause. A fever is the body’s natural response to infection, inflammation, illness, or injury. If your dog has a fever, the fever itself isn’t the whole picture – but rather it’s a symptom of another underlying problem which could require further attention.

This is why it’s important to check your dog’s temperature regularly, particularly if you’re concerned that they’re unwell.

What is a Dog’s Normal Temperature?

Dogs run a little hotter than humans: their average body temperature sits between 37.5°C and 39.2°C – and any reading over this constitutes a fever. If you’ve got an at-home thermometer, it’s a good idea to check your dog’s temperature regularly to ensure their maintaining an average temperature – especially if they seem off or are showing signs of illness.

Symptoms of Fever in Dogs

While a fever is a symptom and not a sickness, if your dog has a fever – then they may be showing other symptoms of illness. The most common ones are:

• A hot, dry nose
• Warm ears and/or paws
• Red eyes
• Lethargy
• Shivering or trembling
• Loss of appetite
• Coughing or sneezing
• Vomiting or diarrhea
• Dehydration (and dark urine)

If your dog is showing any of these symptoms (or a combination of a few of them) then it’s a good idea to check their temperature.

How to Check Your Dog’s Temperature

First off, it’s important to be careful and patient with your dog when checking their temperature as it can be an uncomfortable experience for them. If your dog is nervous, you’re best using a non-invasive device like an underarm thermometer and give them praise and treats as you go to distract them.

Step-by-Step Guide to Check Your Dog’s Temperature

1. Choose and Prepare Your Thermometer: Traditional pet thermometers take temperature by being inserted in the dog’s rectum or ear. Rectal thermometers take reliable results but tend to cause a degree of discomfort to the dog. Ear thermometers are slightly less invasive, but they tend to be slightly harder to use. Newly available and PETstock recommended are underarm thermometers, which take temperature under your dog’s foreleg. If you’re using a rectal thermometer, apply a small amount of lubricant (such as petroleum jelly) to the tip of the thermometer. If using an ear thermometer, make sure your dog’s ear is clean and dry before you proceed. If you’re using an underarm thermometer, no preparation is needed.

2. Hold Your Dog in Position: You might need two people for this task, depending on what thermometer you’re using.
If you’re using a rectal thermometer, have a helper hold your dog in place. Make sure you speak to them soothingly and offer treats as you go as a distraction. Gently lift your dog’s tail and insert the thermometer into them (don’t go too deep, 1-2 inches is sufficient!) Hold the thermometer in place until it beeps.
If using an ear thermometer, gently insert the tip of the thermometer into your dog’s ear canal and hold it in place until it beeps.
If you’re using an underarm thermometer, simply place it under your dog’s foreleg and wait until it beeps.

3. Interpret the Results: If your dog’s body temperature is normal, it should return a result of 37.5°C and 39.2°C and anything above 39.4°C is considered a fever. If your dog has a fever, follow our tips to keep them comfortable (further below) and take them to the vet if it persists.

4. Clean the Thermometer: If using a rectal and ear thermometer, make sure you clean it after every use with alcohol or other disinfectant before storing it.

Treating a Fever In Dogs

If your dog has a fever, the treatment for it will depend on what is causing it. In most cases, the underlying cause will need to be addressed. We’ll explore the causes for fever in more detail below, but the treatment could be:

• Antibiotics or antifungal medications if your dog has an infection.
• Steroids or immunosuppressive drugs if your dog is diagnosed with an autoimmune disease.
• Pain-relief medications if your dog is injured.
• Changing medications if your dog’s fever is in response to prescribed medications.
• Dousing your dog in cool water and hydrating them if their fever is a response to heatstroke.

At-home Treatment for Dogs with a Fever

Here are our top tips for bringing a fever down at home:

• Provide plenty of fresh drinking water.
• Use cooling collars or mats to take their temperature down.
• Douse your dog’s forehead, ears and paws with cool water (make sure you use cool water and don’t shock their system with ice-cold water)
  If your dog’s fever persists for 24 hours, you must take them to a vet.

Why Does My Dog Have a Fever?

Ahhh…the million-dollar question. Unfortunately, there’s no one answer to this – but these are the more common culprits.

Causes of Fever in Dogs

1. Infection

In most instances, a fever is a symptom of a bacterial, viral, or fungal infection. Common infections which can cause a fever include:

• Ear infections
• Urinary tract infections
• Respiratory infections
• Tick-borne diseases (like Lyme disease)
• Canine influenza
• Parvovirus

It’s important that your dog is officially diagnosed if they’ve got an infection so they can receive the proper treatment and care, so be sure to take your dog to the vet if you suspect they’ve got an infection.

2. Autoimmune Disease

In rarer cases, if your dog has persistent fevers they may be suffering from an autoimmune disease. These are caused when the immune system attacks the body's own tissues. These can cause a fever in dogs, along with other symptoms. Some of the more common autoimmune diseases include:

• Lupus
• Rheumatoid arthritis
• Inflammatory bowel disease
• Though not strictly speaking an autoimmune disease, some cancers can also cause fevers in dogs.

Autoimmune diseases require long-term care, so it’s important you take your dog to the vet and receive a proper diagnosis.

3. Injury

Fever in dogs can also be a by-product of physical injury. This is because the dog’s immune system responds to the injury, resulting in an elevated body temperature. Some common injuries that can cause fever include:

• Burns
• Bites
• Trauma
  If your dog suffers a physical injury, it’s critical they’re professionally examined as many wounds pose a risk of infection – they will need to be properly dressed and some will require antibiotics. If you’ve already been to the vet for the injury in question, just keep your dog hydrated and cool while they heal and monitor their temperature to ensure it tracks down to normal.

4. Adverse Response to Medication

Certain medications can cause a fever in dogs as a side effect. These includes antibiotics, anti-seizure medications, and corticosteroids.

If your dog has a fever following putting them on a new medication, consult your vet as there is likely a different medication they can take.

5. Heatstroke

Heatstroke is a dangerous affliction that occurs when your dog’s body temperature is rising faster than your dog’s cooling mechanisms can cope with. It’s of particular concern on hot days, particularly if your dog is in poorly ventilated areas.

Heatstroke can be deadly if not treated quickly, so if your dog is overheating be sure to cool them down immediately and seek veterinary care.

FAQS for Fever in Dogs

Can stress cause a fever in dogs?

Yes, stress can cause a fever in dogs. It can be caused by a change in environment, loud noises, or separation anxiety. Read more about separation anxiety here.

Can humans catch a fever from a dog?

Most fevers in dogs are caused by infections that are specific to dogs and are not contagious to humans. However, it's important to practice good hygiene when caring for a sick dog to prevent the spread of any potential infection.
###Can I give my dog over-the-counter medications to reduce their fever?
Never give your dog over-the-counter medication without first consulting with your vet.

Should I take my dog to the vet if they have a fever?

If your dog has a slight temperature or is on the warm side, monitor them for the next 24 hours and ensure their temperature is trending towards normal. If their temperature is above 39.4°C, you should call your vet. You should also take your dog to the vet without delay if they have other severe symptoms such as vomiting, diarrhea, or difficulty breathing or if your dog has a fever and a known underlying medical condition.