Get

In Your Inbox

Catster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Why Does My Cat Have a Fever? 5 Vet-Reviewed Common Causes

Share

digital thermometer showing a cat has a fever

Cats normally have temperatures between 100º F and 102.5º F; anything above that is considered to be a fever, also known as pyrexia. Fevers play an essential role in keeping cats healthy as they trigger their immune systems to shift into high gear and make it difficult for viruses and bacteria to proliferate.

Fever can be caused by parasites, trauma, and infections; anything that triggers an inflammatory response. Cats with fevers often show other signs of illness, such as a lack of energy and interest in eating and drinking. Cats feeling feverish also sometimes shiver, hide, and show little interest in activities such as grooming themselves.

It’s not always easy to tell if your cat has a fever, as their body temperature is higher than ours, but if their ears feel quite warm, especially if the outside temperature isn’t hot, this can be a sign that your cat has a fever. If you think your cat has a fever that lasts more than 24 hours, or if they also seem unwell, it is time to make an appointment with your vet. They will be able to examine your cat and run tests to find out what is causing the fever, and get them the right treatment.

divider cat paws oct 2024

The 5 Common Causes Why Cat’s Have Fever

1. Parasites

Cats can be infected by various parasites, but the two most likely to cause fevers are toxoplasmosis and cytauxzoonosis. Cats infected with toxoplasmosis rarely show signs of infection, but when they do, they typically include a lack of interest in eating, weight loss, and fever. Some may develop jaundice and difficulty breathing. Treatment usually involves antibiotics, and cats who recover generally do just fine.

Cytauxzoonosis is a tick-borne disease, caused by a protozoa that results in widespread inflammation and organ and tissue damage. Infections are commonly seen when ticks are at their busiest, generally between April and September. Signs of cytauxzoonosis infections include lack of interest in eating, vomiting, weakness, and jaundice. Most cats suffering from cytauxzoonosis infections have extremely high fevers.

Fast intervention is essential with cytauxzoonosis, and cats must spend a few days in the hospital to get back on their feet. The treatment usually involves antiprotozoal medication and supportive care.

sick cat lying on the floor
Image Credit: Oporty786, Shutterstock

2. Cancer

Several types of cancer can cause cats to develop fevers, but lymphoma tends to be the type that impacts the most felines. Other cancers that are commonly found in cats include soft-tissue sarcomas and squamous cell carcinomas.

Regular medical checkups ensure that severe medical conditions (such as cancer) are diagnosed as quickly as possible, which can lead to better outcomes over time.


3. Infections

Bacterial, fungal, and viral infections can all cause fevers in cats. Although the types of infections that lead to fevers can occur anywhere in a cat’s body, viral infections that affect the upper respiratory tract are particularly common; feline calicivirus and feline herpes virus are frequently encountered, culprits.

Feline leukemia virus, feline immunodeficiency virus (FIV), and feline coronavirus (also known as feline infectious peritonitis, or FIP) are relatively common viruses in the cat population, and can all present with fever and lethargy.

Cats that get into fights can end up with infections that often turn into abscesses, a pocket of pus under the skin. Fever, lethargy, and pain are usually the first signs of an abscess brewing. Feline lower urinary tract disease, including infection, are also common causes of inflammation and fever in cats.

Antibiotics are prescribed to help cats suffering from bacterial infections get back on their feet. Some viral infections respond well to supportive care, while others can have lifelong effects, or be fatal.

If you suspect your cat has an infection, we advise you to speak to a vet.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content for PangoVet2 save money


4. Brain Trauma

Brain injuries can cause problems with temperature regulation, which can lead some cats to spike fevers or have abnormally low body temperatures. There are two steps involved when cats experience brain trauma; there’s the initial injury and then the problems that crop up as a result.

Common secondary brain injuries include bleeding blood vessels and severe tissue swelling. Other signs of brain trauma include pupils of different sizes and a particularly slow heart rate. Brain trauma can be caused by something sudden, like being hit by a car, but long-term health problems such as high blood pressure, blood clotting disorders, and heart attacks can also cause problems.


5. Heat Exhaustion and Stroke

Heat exhaustion and stroke are caused when cats are exposed to hot, humid temperatures for too long, and are unable to cool down. Outdoor cats are more commonly affected, but indoor cats are also susceptible, with sunny spots and indoor heating.

Overweight pets, kittens, brachycephalic cats (eg. Persians), and those with conditions such as diabetes, kidney disease, and heart problems, are also more at risk. Heat exhaustion is diagnosed when cats’ temperatures reach between 103º F and 104º F. Signs to look out for include diarrhea, vomiting, rapid breathing, and seizures.

sick cat lying on blanket
Image credit: one photo, Shutterstock

divider cat faces oct 2024

Frequent Asked Questions

Are Fevers Always Caused by an Illness?

No. Benign activities, including exercise and excitement, can cause cats’ temperatures to be a bit higher than normal.

Are There Other Potential Causes of Elevated Temperatures in Cats?

Yes. Some types of medication can cause cats to have temperatures, as can various inflammatory conditions.

a sick siberian cat being carried by owner
Image Credit: Anna Krivitskaya

How Do Veterinarians Determine What’s Causing a Cat’s Fever?

Veterinarians rely on information provided by pet parents to get started. Tests for feline leukemia virus and feline immunodeficiency virus are frequently part of the workup. Urinalysis and fecal tests are commonly ordered, and imaging studies, such as ultrasounds and X-rays, are also used.

divider cat paw scratch oct 2024

Conclusion

Fevers are commonly seen in cats who aren’t feeling well. They actually play an important role in the immune function since they help cats fight infection. A temperature between 100º F and 102.5º F is considered normal for cats. While many fevers go away with supportive care, pets who don’t start feeling better relatively quickly should receive a thorough veterinary evaluation, and those with high fevers should receive immediate medical attention.

Fevers can have several causes, including infections, trauma, parasites, and cancer, and getting cats back on their feet involves identifying the cause of the problem and providing the appropriate treatment.


Featured Image Credit: Evgeniy Kalinovskiy, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything cat

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.




How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Catster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.


Catster's Digital Magazine is Back!

Vet-approved health & behavior advice

Real cat stories & community features

Chatting About the Rainbow Bridge, Euthanasia, and Laughter During Grief | Chatty Cattys, Episode 24

If you’ve ever felt the loss of a beloved cat, or are dreading the day when your pet crosses the rainbow bridge, you’ll...

The Simple Reasons Cats Refuse to Let Anyone Use the Bathroom Alone

Cats have an extraordinary talent for making themselves present in the most inconvenient places, and the bathroom ranks near the top of the...

A Paw-sitive Milestone: Canada Officially Becomes a Declaw-Free Nation

Canada has officially become a declaw-free nation. On May 25, 2026, a new regulation was filed in Ontario under the Provincial Animal Welfare...

The Surprisingly Simple Ways to Help a Cat With Hairballs

Cats spend an astonishing amount of time grooming. It is part hygiene routine, part comfort ritual, and part instinct that traces back generations....

More related

Cat Ears Drooping: Signs, Causes & What to Do (Vet Answer)

Did you know that, unlike dogs, there’s only one breed of cat with ears that aren’t fully upright? That’s right, and those are...

10 Pet Friendly Hotels in Florida (2026 Update)

When the weather cools, ever-sunny Florida locales can become impossible to resist. Being a responsible pet parent, keeping your fur babies from enjoying...

Pittsburgh Refrigerator Cat: The Myth Explained

Have you ever heard of the Pittsburgh refrigerator cat? If not, you’re certainly not alone. We hadn’t heard about it either. Don’t feel...

Can Cats Be Sexually Attracted to Humans? Dispelling the Myths (Vet-Verified)

Our relationship with our animal companions has evolved through the ages. When we once considered cats to be mere mousers, we’ve since invited...

Keep reading

How Long Can a Cat Go Without Peeing? Vet Reviewed Facts & FAQ

As a living being, a healthy cat’s urinary system is always functioning and constantly producing urine. On average, healthy cats urinate two to four times daily, however, it depends on how much water and food they had in the previous...

cat outside the litter box

Why Do Cats Knock Things Over? 3 Vet-Reviewed Reasons

Cats are curious animals. They can be cute and cuddly one minute, then start knocking things over the next. They might even break belongings that are difficult or impossible to replace! We put up with these antics because we love...

A Thai cat playing with a white mug

Can Cats Eat Pringles? Vet-Reviewed Facts & FAQ

Does your cat come running every time you pop open a can of Pringles because he loves the funny-shaped potato chips? If you’re wondering if cats can eat Pringles, you should know that Pringles and other chips aren’t good for...

Can Cats Eat Pringles

Why Does My Cat Have Whiskers on Their Eyebrows? Vet-Verified Facts & Functions

Though whiskers above the mouth are a standout feature in cat anatomy, whiskers in other areas are less conspicuous. In addition to the area above their mouths, cats have whiskers on their chins, forelegs, around the ears, and above the...

cat orange eyes

Why Does My Cat Throw Up After Eating? 8 Vet-Reviewed Reasons & Solutions

If your cat starts throwing up after they eat, it’s obviously very alarming behavior that you want to get to the bottom of as soon as possible. But what exactly could be the cause of your kitty’s stomach issues? Vomiting...

sick cat vomiting the food on a white background

Can Cats Get Laryngitis? Vet-Verified Health Facts

Your usually vocal cat suddenly struggles to find their voice. They open their mouths, but either nothing comes out at all, or all they’re able to muster is a quiet, raspy meow; what gives? They could be dealing with feline...

Cat-meowing

Outdoor Plants That Are Toxic to Cats: 10 to Avoid (Vet-Reviewed)

Cats are curious creatures and will often show interest in plants, grasses, trees, and dangling leaves. However, it’s important to be informed on this topic of greenery in your garden. A quick lick or nibble can result in your pet...

Wisteria plant

Do Cats Feel Sad in the Same Way Humans Do? Vet-Reviewed Feline Behavior

A cat’s brain is very complex, and very similar to a human’s brain in some ways. This enables them to experience a range of different emotions, such as sadness, anger, fear, joy, and surprise. However, cats will not show emotions...

sad looking cat lying on a table

Love Cats? So Do We! Join the Catster Community

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.




Sign up for the Catster Email Newsletter

Stay informed with expert pet care insights delivered straight to your inbox! Discover professional guidance on animal behavior, feeding tips, trusted product picks, and much more.