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.


Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

Ask Dr. Paola – Help! My Male Cat Gets Into Fights! (March 9, 2026)

Welcome to our “Ask Dr. Paola” series, where every Monday we bring expert advice straight from Dr. Paola Cuevas (MVZ) to help our...

Why Your Cat’s Poop Smells Like a Biohazard

Nobody enjoys litter box duty, but sometimes it gets unbearable. The smell hits you from across the room. You’re scooping faster, lighting candles,...

RIP Your Furniture? Not With This Guide to Cat Scratch Damage Control

Your couch looks like it survived a minor apocalypse. The curtains have mysterious vertical shreds. That new rug you splurged on is already...

Celebrating 15 Years as the Most Popular Resident of No. 10 Downing Street

For almost 300 years, a rather unassuming Georgian building of black bricks with a shiny black door has been the official residence and...

More related

How Big Is a Cat Brain? Vet Explains Feline Anatomy

If you own a cat, you’ve probably wondered how intelligent they are. After all, sometimes they can be silly goofballs, while at other...

Is My Cat’s Jaw Broken? Vet-Reviewed Signs to Be Aware

Cats instinctively hide their pain, so it can be difficult to tell if something is amiss. If your cat is in pain, you...

Harlequin Cat: Info, Pictures, Rarity & History

A harlequin cat has a specific coat coloration that sets them apart from other felines. They’re primarily white, with only around 25% of...

10 Vet-Reviewed Facts About Cats’ Teeth: Feline Anatomy Explained

Your cat’s teeth are important tools that they need for eating and fighting, but they are also quite small and surprisingly delicate, and...

Keep reading

Do Cats Like the Taste of Sweet Things? Vet-Approved Facts & Safety Tips

If you own a dog, you probably already know that chocolate is toxic for them. But what about cats? We don’t see them going near chocolates and sweets too often. Does this mean cats don’t like the taste of sweets?...

Cupcake Frosting

Can Cats Eat Pancakes? Vet-Verified Nutritional Facts & Health Advice

If you have a family tradition of eating pancakes for breakfast on a Saturday morning, you might feel bad for excluding your cat. They are a member of the family, after all. Of course, this will leave you wondering if...

Can Cats Eat Pancakes

Can Cats Eat Beef Wellington? Vet-Reviewed Risks & Alternatives

Beef Wellington is a popular dish for the holidays or dinner parties. It is an impressive dish to make, and you may want to share it with your cat. However, Beef Wellington isn’t safe for cats to eat. While it...

Can Cats Eat Beef Wellington

Are Polka Dot Plants Toxic to Cats? Vet-Reviewed Houseplants Examined

The polka dot plant (Hypoestes phyllostachya) is also known as the pink polka dot plant, the measles plant, baby’s tears, or freckle face. The green leaves have freckled markings of pink that look like polka dots. The more sunlight the...

Catster_Are Polka Dot Plants Toxic to Cats

How to Socialize a Shy Cat Who Frequently Hides: 7 Vet Approved Tips

If you are a cat parent who constantly struggles to get their fur baby out of their secret hiding spot, you have come to the right place. The good news is that it is entirely possible to help a shy...

scared cat hiding behind the door

Cat Poop Chart: Colors, Consistency & More (Vet-Reviewed)

We all know cleaning the litter box is an unpleasant but crucial part of pet ownership. You don’t want to spend more time around your cat’s waste than you have to, but as you’re cleaning the box, it’s worth taking...

Tabby cat sitting in a litter box and look to the camera

What Temperature Do Cats Like? Vet-Verified Climate Tips & FAQ

We all know that cats like to be warm and cozy, whether they’re curled up in a donut bed or splayed out in front of a fireplace. It’s not uncommon to spot your cat spread out in a sunbeam, even...

a tabby cat lying on the floor

Why Is My Cat So Affectionate All of a Sudden? 4 Vet-Reviewed Reasons

We can all agree that receiving affection from our cats is rarely a bad thing. However, if your cat is suddenly affectionate, you may be a bit suspicious as to why your cat won’t leave your side. Any little change...

tabby cat lying on a womans chest

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.