By Jennifer Copley (Last Updated 12 May 2011)
The Cat’s Personality, Temperament, or Vocalization Changes
A cat may suddenly become antisocial, hostile, or even aggressive when she doesn’t feel well. She may also engage in unusual vocalizations, such as chronic howling for no apparent reason.
The Cat is Lethargic and/or Does Not Groom
When a cat appears listless and shows little interest in the people, toys, and activities that she used to love, there is usually something wrong. In some cases the cause may be psychological rather than physical, but medical problems should be ruled out before treating the issue as psychological. A particularly bad sign is when a cat ceases to clean herself, allowing her coat to become dull, greasy, or dirty.
The Cat has Diarrhea
An occasional single bout of diarrhea is probably nothing to worry about unless there are other symptoms or blood in the stool. However, multiple bouts of diarrhea can indicate a serious problem, and a cat (particularly a kitten or an elderly feline) can become dangerously dehydrated quite rapidly.
The Cat is Constipated
A cat that has infrequent bowel movements and strains or cries at the litter box, producing hard dry stools, is probably constipated. Bouts of constipation are common in older cats, but constipation may occur in younger cats as well. If a cat appears to be constipated or stops defecating altogether, a visit to the veterinarian is necessary to rule out more serious, life-threatening problems before attempting to treat the problem with dietary changes.
See Cat Constipation Causes, Symptoms, and Remedies for more information.
The Cat Drinks Excessively
There are a number of illnesses that can cause a cat to drink water excessively, such as chronic renal failure (CRF), also known as chronic insufficiency (CRI) or chronic kidney disease (CKD), and hyperthyroidism, which causes a ravenous appetite, hyperactivity, and weight loss as well.
The Cat has Bald Patches or Sores
Hair loss or sores on a cat’s skin are often caused by allergies or external parasites such as fleas (see Natural Flea Control for safe, non-toxic flea eradication methods). In such cases, the cat will often scratch or groom excessively. Some cats also pull out their fur or groom excessively as a result of generalized anxiety or nervousness about a specific situation, such as bullying by another animal or a move to a new home. When these symptoms are caused by psychological issues rather than medical problems, the condition is called psychogenic alopecia.
The Cat Stops Eating and/or Loses Weight
There are a number of reasons why cats will stop eating, so this symptom doesn’t always indicate an illness. However, it’s a good idea to take the cat in for a veterinary check-up if she doesn’t eat for more than 24 hours or has any additional symptoms. Weight loss, whether the cat is eating or not, is usually a symptom of illness or parasite infestation.
The Cat Vomits Persistently
Most cats will vomit up a hairball from time to time. This is usually harmless (though occasionally a cat will suffer constipation or even more serious problems as a result of hairballs). There are safe hairball prevention treatments that can reduce or eliminate hairball-related vomiting.
Cats will also sometimes gobble their food too quickly and become sick as a result. A single incident of vomiting is usually nothing to worry about unless there is blood in the vomit or there are additional symptoms. However, persistent repetitive vomiting, sporadic vomiting over the course of several days, vomiting up blood or material that resembles feces, projectile vomiting, or vomiting worms all require a trip to the veterinarian.
See Why Cats Vomit for more detailed information on this symptom.
The Cat Begins Urinating or Defecating Outside the Litter Box
Urinating or defecating outside the litter box can be caused by anxiety, problems with the litter box, or medical conditions such as lower urinary tract disease, intestinal blockage, kidney problems, and other illnesses that make urination or defecation difficult or painful. Litter box issues should be referred to a veterinarian before treating them as behavioural problems.
Other Symptoms of Illness in Cats and Kittens
Some additional symptoms of illness in felines include:
- Gagging or retching
- Wheezing/noisy breathing/difficulty breathing
- Sneezing and/or runny nose
- Eye discharge (runny eyes)
- Sudden, rapid, or excessive weight loss
- Lumps under the skin/bumps on the skin
- Abdominal swelling
- Blood in the stool
- Blood in the urine
- Increased hunger
When in doubt as to whether a symptom indicates a serious illness, consulting a veterinarian to be on the safe side is recommended.
For more cat articles, see the main Cats page.
- Commings, Karen. (1999). Guide to Owning an Exotic Shorthair Cat. Neptune City: NJ: Chelsea House Publishers/T.F.H. Publishcations, Inc.
- Eldredge, D.M.,DVM, Carlson, D.G., DVM, Carlson,L.D., DVM & Giffin, J.M., MD. (2008). Cat Owner’s Home Veterinary Handbook, Third Edition. Hoboken, NJ: Wiley Publishing, Inc.
- Merck & Co., Inc., Eds. Cynthia M. Kahn, BA, MA & Scott Line, DVM, PhD, Dipl ACVB. (2007). The Merck/Merial Manual for Pet Health, Home Edition. Whitehouse Stations, NJ: The Merck Publishing Group.