Recognizing the Signs of Illness in Cats

By Malcolm Weir, DVM, MSc, MPH; Tammy Hunter, DVM; Cheryl Yuill, DVM, MSc, CVH

My cat seems fine. Could there be a problem?

Although cats are predators, in nature, larger predators prey on them. Any obvious sign of illness would alert other predators that the animal is vulnerable – sick or old animals make an easy target. For that reason, cats have evolved to hide signs of illness and pain.

In the early stages of illness, often the only thing that a cat owner may notice is that the cat has become quiet and withdrawn. Unfortunately, this also means a cat may be very sick before the owner realizes something is wrong.

Through training and experience, veterinarians may notice subtle signs that a cat is developing a health problem, which is one of the main reasons why the American Veterinary Medical Association and other veterinary experts recommend twice-yearly wellness examinations for the average adult cat. Delaying your cat’s veterinary visit until there are obvious signs of illness may mean that heroic measures will be required to treat the problem.

"Cats have evolved to hide signs of illness and pain."

With some understanding of how cats show symptoms of illness, you can recognize early warning signs and know what information you need to give your veterinarian.

What things should I look for?

Cats that are ill usually show changes in overall appearance, energy level, sociability, coat appearance, and/or amount of shedding, appetite, litter box usage, breathing, or discharge from the eyes or nose. In general, any sudden change should alert you that your cat needs veterinary attention.

What changes would I see in overall appearance?

Cats that are not feeling well may just look a little “off.” The cat might sit in a hunched position, might not move as gracefully as before, might not lift its head properly, might have a head tilt, or might carry its tail differently. Sometimes, there isn’t any one thing that stands out, but a variety of subtle changes.

Dehydration is a common problem in cats that are not well. To see if your cat is dehydrated, gently grasp the skin near the shoulder blades, pull it up and away from her body, then let go. The skin should snap back right away. Skin that does not snap back into place, but stays “tented up”, usually indicates dehydration, a condition that needs to be treated immediately.

Cats with a chronic illness may develop slow and subtle weight loss that is only obvious when you run your hands along the ribs and spine. Cats that suddenly lose weight, particularly if they were previously overweight, are usually suffering from a metabolic disease such as diabetes or hyperthyroidism.

What changes in sociability or energy level would indicate that my cat might be sick?

Sick cats usually become withdrawn and may hide, although this depends on the personality of the individual cat. Some cats become clingier or demand more attention, while others just become cranky.

Generally, sick cats also have lower energy levels. The only thing you may notice is that your cat sleeps more, does not play as much, or is restless.

With some diseases, especially hyperthyroidism, your cat’s energy level may seem to increase to the point of hyperactivity. Cats with hyperthyroidism are often restless at night and may suddenly begin howling or waking family members up.

Cats with arthritis or other joint problems may have difficulty moving around and may no longer jump up on furniture or counters, or they may change how they jump onto higher surfaces. If your cat suddenly is unable to use its back legs, she should be seen by your veterinarian immediately.

What changes would I see in coat appearance and amount of shedding?

Cats that are not feeling well do not tend to groom themselves well. Therefore, you will usually see a messy or greasy coat, mats of fur, or clumps of loose hair. In some cases, you will see a difference in the coat’s shine or an increased amount of dandruff.

"Cats that are not feeling well do not tend to groom themselves well."

Cats that groom themselves excessively may also have a problem. Excessive grooming may be a reaction to a skin problem such as allergies; a parasite such as fleas, mites, or ringworm; pain such as that from arthritis or a bladder problem; or stress. These cats might over-groom all parts of their body, or they may lick themselves in one area so much that they develop bald spots, and the skin beneath may be red and raw or may have a rash.

What changes should I look for in appetite or thirst?

Sick cats may eat less or more than usual, and they may drink less or more than usual, so any change in appetite or thirst may be of concern. Cats with dental disease may seem to be picky about their food. Cats that have some metabolic diseases such as hyperthyroidism or diabetes mellitus may have a hearty appetite and increased thirst. Cats with liver or kidney problems often lose their appetite, but have increased thirst.

"Any change in appetite or thirst may be of concern."

If your cat has not eaten properly for 24 hours, seek immediate veterinary attention. Cats that have not eaten (anorexic cats) are prone to developing a condition called hepatic lipidosis or fatty liver disease, in which the cat’s appetite becomes completely suppressed for weeks. See handout “Hepatic Lipidosis in Cats (Fatty Liver Syndrome in Cats)” for more information. If fatty liver syndrome develops, your cat will require extensive medical management for several weeks to months before things get back to normal.

What changes should I look for in the litter box?

Both diarrhea and constipation are indicators of disease in cats. Diarrhea is usually easy to recognize in the litter box, but constipation can be harder to notice. Small, hard, dry stools are never normal and are often an early indication of kidney disease.

Increased amounts of urine in the box indicate an inability to properly conserve water and may mean that your cat is developing kidney or liver problems, or diabetes mellitus.

Decreased amounts of urine in the litter box indicates some sort of kidney or bladder problem, especially if the cat spends more time going in and out of the box or strains when in the box. Cats with a urinary tract problem often lick excessively at their genitals. If you notice that your cat does not seem to be producing as much urine as usual, or the clumps of urine are small, you should seek immediate veterinary attention. Lack of urination is a life-threatening emergency.

What changes should I look for in breathing?

Breathing difficulty, such as shallow breathing, mouth breathing, or panting, may indicate a problem with the airways or lungs. Cats with breathing problems often extend their head and neck or may be unable to sleep in a normal position. Repeated bouts of sneezing or coughing are signs of health issues.

What eye changes may be present in a sick cat?

Signs of trouble include droopy eyelids; discharges that are green, yellow, or white; squinting; pupils that are dilated or constricted; or anisocoria (one pupil dilated and the other constricted). Sick cats often have elevated third eyelids. The third eyelid is located beneath the lower eyelid and, in a sick cat, it will cover part of the eyeball. Any abnormality with the eyes can result in blindness; if in doubt, do not delay - see your veterinarian.

Are there any other symptoms?

It is not normal for a healthy cat to have any discharge from the nose, debris in the ears, excessive salivation, bad breath, or unusual odor from other parts of the body. Vomiting is a cause for alarm, particularly vomiting of clear foamy fluid or bile-tinged material. Gums, skin, or eyes that are pale may indicate anemia, while a yellow tint may indicate jaundice, and a bluish tint may indicate a lack of oxygen. Delaying treatment for these disorders, even by a few hours, can be fatal.

"Err on the side of caution and make an appointment for a veterinary examination as soon as possible if your cat does not seem right to you."

Because signs of illness can be very subtle, err on the side of caution and make an appointment for a veterinary examination as soon as possible if your cat does not seem right to you. If you make it a habit to give your cat a general once-over on a regular basis, you will have an idea of what is normal and will be more likely to catch minor problems before they become major health issues.

If your cat does not eat for more than 24 hours, or if you notice any breathing problems, straining in the litter box, or eye abnormalities, seek immediate veterinary attention. If you have any concerns or questions about your cat’s health, visit or call your veterinarian’s office – they are your best and most reliable resource to ensure your pet’s well-being and health.

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