Common Cat Illnesses: Symptoms, Causes, and Treatment Options

The most common cat illnesses are upper respiratory infections, feline leukemia virus, chronic kidney disease, diabetes mellitus, and dental disease. Since cats can hide discomfort well, the early signs tend to be small, like changes in thirst, appetite, weight, or litter box habits. Some can be manageable when a vet catches them early, which is why routine checkups matter.

Cats are pros at hiding pain. A sick cat will often act completely normal right up until it can’t, which is why the early signs slip past even the most attentive owners.

This guide covers the illnesses cats run into most, what is usually behind them, and the symptoms worth watching. You will also learn about how vets diagnose and treat each illness. The sooner you catch a problem, the better your cat’s odds.

What Are the Most Common Cat Illnesses?

Upper Respiratory Infections

An upper respiratory infection is about as common as cat illnesses get. They’re caused by one of two viruses in most cases: feline herpesvirus or feline calicivirus. Feline calicivirus alone causes about half of the respiratory infections in cats. Put a group of cats together in a multi-cat household or a shelter, and these diseases spread fast. The first signs you will notice are sneezing, runny eyes, nasal discharge, and congestion.

Feline Leukemia and Other Viruses

• Feline Leukemia Virus: This illness wears a cat’s immune system down. It affects about 2 to 3% of cats in the United States and can raise the odds of certain cancers, including lymphoma.
• Feline Immunodeficiency Virus: A cousin of feline leukemia virus, this is slow to act and quietly lowers immunity, sometimes years after the initial infection.
• Feline Panleukopenia: This highly contagious parvovirus can be dangerous to both indoor and outdoor cats. Vaccines help prevent it.

An infected cat can pass some of these viruses to other cats, so testing and vaccination are both important.

Diabetes Mellitus

Diabetes mellitus throws off a cat’s ability to manage blood sugar. The body either stops making enough insulin or stops responding to it. Glucose piles up in the blood instead of fueling the body.

Watch for:

• More thirst than usual
• Frequent trips to the litter box
• Bigger appetite
• Weight loss

Let it go untreated, and it can spiral into complications, including nerve problems that leave the back legs weak.

Chronic Kidney Disease

Over time, the kidneys can’t filter waste the way they used to, which can cause chronic kidney disease in older cats. Estimates suggest it occurs in around 30 to 50% of cats older than 15 years. Bloodwork that catches it early is your best tool for slowing it down, and it can help protect the cat’s lifespan.

Dental Disease

A loud noise or a stranger can put your cat on alert. A startled cat freezes and stares while it decides what to do next. Watch for wide eyes, flattened ears, and a tense posture. Give your feline friend space and a clear exit route rather than forcing contact.

What Symptoms Should Cat Owners Watch For?

Cats rarely make a big show of being sick. The clues are small: a shift in how they eat, drink, act, or use the litter box. The symptoms below tend to point toward an upper respiratory infection, diabetes or kidney disease, dental disease, diabetes or hyperthyroidism, or feline leukemia or anemia.

 When Is a Symptom an Emergency?

Some symptoms simply can’t wait. Notice any of these and call your vet right away:

• Trouble Breathing: Open-mouth or labored breathing counts as one of the most severe emergency situations for a cat.
• Straining with No Urine: A cat parked in the litter box with nothing coming out needs help within hours.
• Refusing Food for More Than a Day: A cat that stops eating may be telling you something else is wrong, and going without food can quickly damage a cat’s liver.
• Repeated Vomiting: Vomiting that doesn’t stop can mean poisoning, intestinal parasites, or something wrong with the organs.

What Causes Cat Illnesses and Which Cats Are Most at Risk?

Whether a cat gets sick comes down to a handful of factors. Some are in the hands of the pet owner, but others simply become more common as cats get older.

Warning Signs

• Age: The older the cat, the higher the chances of kidney disease, dental disease, and diabetes. Because kittens’ immune systems are still developing, they can be more susceptible to infections like upper respiratory infection and feline panleukopenia.
• Outdoor Access: Outdoor cats rub shoulders with other cats and collect viruses and intestinal parasites far more than an indoor cat ever will.
• A Crowded Home: Something like feline herpesvirus tears through a multi-cat household.
• Missed Vaccines: Falling behind on routine vaccines can put a cat at risk of contracting feline panleukopenia and other infections.
• Extra Weight: Those extra pounds can be a common contributor to feline diabetes.
• Cat Gender: Risk factors for certain medical conditions can depend on the cat’s gender. For example, male cats carry an added risk of urinary blockages, which becomes a medical emergency the moment they can’t urinate.

How Are Common Cat Illnesses Diagnosed and Treated?

Treatment only works when the diagnosis is right. Your veterinarian usually starts with a physical exam, then runs tests to figure out what is actually going on.

How Does a Vet Diagnose a Sick Cat?

The physical exam is where the vet looks over your cat’s teeth, weight, and body for anything out of place. Bloodwork and urine tests can help identify kidney disease, diabetes, or an infection. Get those lab results back the same day, and treatment can start sooner.

What Are the Treatment Options?

Once the cat is diagnosed, the plan follows the illness:

• Upper Respiratory Infections: Rest, fluids, and supportive care carry most cats through, though a few need medication to shake it.
• Diabetes: For a lot of cats, that means daily insulin injections and a diet change to hold glucose levels steady.
• Kidney Disease: A special diet, fluids, and medication keep things stable as the years go on.
• Dental Disease: A professional cleaning lifts off the tartar, and the vet treats or pulls whatever teeth are too far gone.
• Viral Infections: Feline leukemia virus and feline immunodeficiency virus have no cure, but solid care keeps an infected cat comfortable.

Keep up with vaccines, parasite prevention, and routine checkups, and you lower the odds of a lot of these illnesses while catching the rest early.

Coastal Veterinary Care: Your Partner in Feline Health

You are the one who notices when something is not right with your cat. Our Fear Free Certified and AAHA-accredited facility in Myrtle Beach backs you up through every stage of your cat’s life, from cat wellness exams to pet dentistry, digital cytology for fast diagnostics, and senior pet care. If your feline companion is showing any of these symptoms, contact Coastal Veterinary Care to schedule an appointment today.