You’re probably familiar with the tried and true method many dog owners have relied on to see if their dog has a fever: Feel his nose. If it’s wet and cold, he’s fine. If it’s hot and dry, he probably has a fever. Simple, right? There's nothing wrong with using this old-time gauge, but sometimes it's more complicated than that, and the nose test alone is often not enough for an accurate assessment of the presence of fever.
What Is a Dog’s Normal Temperature?
Unlike people, who have a normal temperature range of 97.6–99.6F degrees, your dog’s normal temperature is higher: the range is between 99.5 and 102.5F degrees. So now that we know what is normal, let’s look at the signs that tell us if our dog is out of range and running a fever.
What Are the Signs of Fever in Dogs?
Your dog can’t tell you when he has a fever, so you should familiarize yourself with the symptoms that can indicate its presence.
Here are the most common signs:
- Red eyes
- Lethargy/lack of energy
- Warm ears
- Warm, dry nose
- Loss of appetite
What Causes a Fever in Dogs?
An infection or inflammation can produce a fever in pets, as their body attempts to fight it off. They can be internal or external, and include:
- An infected bite, scratch, or cut
- Ear infection
- Urinary tract infection (UTI)
- Infected or abscessed tooth
- An ongoing bacterial or viral disease
- Infection of organs, such as kidneys or lungs
Ingestion of poisonous materials can also cause fever. These include:
- Toxic plants
- Human medications
- Human foods that are toxic to dogs, including the artificial sweetener xylitol
If you think your dog has ingested a toxic substance, contact the Pet Poison Hotline
It’s not uncommon for pets (and humans) to experience a low-grade fever 24–48 hours after a vaccination. This is usually not dangerous and resolves after a day or so, but monitor the situation.
How to Take Your Dog’s Temperature
While it may not be the most enjoyable thing you and your dog will ever do together, accurately assessing his temperature can only be accomplished with a rectal or ear thermometer. Nowadays there are digital thermometers made just for pets. You should have one of these in the first-aid kit you keep for your dog. It can register your his temperature in about 60 seconds, cutting down on his (and your) discomfort.
For a rectal thermometer, first lubricate it with petroleum jelly or baby oil. Gently insert it about an inch into your dog’s anus and then remove it as soon as you get a reading.
Ear thermometers are less invasive, yet still a reliable way to take your dog's temperature. It measures the infrared heat waves that are emitted from the area around the eardrum. The thermometer is placed deep into the horizontal ear canal to obtain an accurate reading. Ear thermometers are usually somewhat more expensive, but your dog will appreciate your willingness to shell out a few more bucks. Read all instructions carefully. Do not use a glass thermometer.
When to Bring Your Dog to the Vet
A dog is considered to have a fever when his temperature reaches 103 degrees or higher. If it does, it’s time to head to the vet’s office. A temperature of 106 degrees or higher can damage a pet’s internal organs and can be fatal, so never wait until it gets to that point.
According to PetMD, once at the vet’s, diagnosing the underlying cause can be tricky. Your vet probably has a record of your dog’s medical history, with information about vaccines, surgeries, allergies, medications, and past illnesses. But the vet may also need to know of any recent physical injuries, ingestion of plants or other toxins, insect bites, and so on. It will also be helpful to note when you first noticed the fever.
After conducting a physical exam, your vet may order routine laboratory tests, such as urinalysis, blood count, or a biochemistry profile. They can offer up useful information about an underlying condition or infection. In the case of infection, your dog may be prescribed medication. More specific testing may also be required.
Sometimes the root cause of the fever can’t be determined. Vets even use an acronym for this: FUO (Fever of Unknown Origin).
How to Reduce a Dog’s Fever
To help reduce a pet’s fever—103 degrees or higher—first apply cool water around his paws and ears. You can use a soaked towel or cloth. Continue to monitor his temperature, and when it drops below 103, you can stop applying the water. See if you can coax him into drinking a bit of water. You will still need to monitor your dog closely, to make sure his fever doesn’t return, and consider taking him to the vet if he exhibits other symptoms. Remember: Better safe than sorry.
Never give your dog (or cat) human medication, such as aspirin or acetaminophen. These are extremely toxic for pets.
Note: This article is designed to help inform you about fever in dogs and is not meant to take the place of a veterinary diagnosis or consultation. If you think your dog might have a fever, contact your vet right away to set up an appointment for an examination and to ensure that your dog receives the safest and most effective treatment.
Sources: PetMD; Canidae; Purina; Merck Veterinary Manual