Cat Illness – Signs of Sickness in Cats

Signs of sickness in cats

Cats are very stoic creatures by nature and it is up to the observant cat owner to keep a watchful eye over them and be aware of small changes in their appearance, behaviour, eating habits etc., which could indicate all is not well. Any sign that your cat is unwell requires veterinary attention.

Your cat can’t tell you when something is wrong so it is important for you, the carer to be observant and watch for clues, and act accordingly. What may seem to be a minor change to you may be indicative of a serious medical issue with your cat, so prompt veterinary attention is always necessary to find out what is happening.

Changes in behaviour:

Inappropriate elimination – Inappropriate elimination can be the result of a behavioural issue or a medical problem. This is why it is extremely important to seek veterinary advice if your cat stops using the litter tray. He/she will run some tests to determine if there is a medical cause if so it can be treated and if it is established that it is a behavioural problem appropriate action can be taken to help your cat resolve this problem.

A cat who is urinating outside the litter tray may have a number of medical conditions such as diabetes mellitus,  kidney failure, FLUTD, urinary tract infection.

Increased/decreased thirst and or appetite – There are many possible reasons why your cat may be eating or drinking more or less, some of which include:

Increased thirst could indicate diabetes mellitus, pyometra, hyperthyroidism. Increased appetite could be caused by hyperthyroidism.

Loss of appetite could be caused by an abscess, anaemia, dehydration, injury or trauma, intestinal obstruction, dental or mouth pain (gingivitis, tooth abscess, stomatitis etc.) or other disorders.

Increased vocalisation – This may be caused by stress, fear, estrus or an underlying medical problem. It is often seen in older cats and can be indicative of pain, sickness, loss of cognitive functions or another medical problem.

Hiding – If your usually outgoing cat suddenly takes to hiding it could have been brought about by fear, anxiety or an underlying medical cause.

Sleeping habits – Sleeping more and lethargy often a sign that something is wrong with your cat.

Change in routine or general behaviour –  If your cat usually greets you when you come home from work, but abruptly stops this it could be a sign that something is wrong with kitty. Is your cat suddenly spending a lot of time in the litter tray, no longer harassing you for food first thing on a morning, or harassing you for food when it hadn’t in the past? Any change, no matter how minor could be a result of a medical condition.

General and physical signs:

Coat appearance – Cats are by nature fastidiously clean and spend a great deal of their day grooming. Poor coat condition can be caused by a multitude of problems, from parasites to malnutrition to skin disorders (such as ringworm, fleas, allergies). The older cat may have problems maintaining it’s grooming regime due to pain caused by conditions such as arthritis or obesity.

Bad breath – Also known as halitosis, bad breath in cats is not normal and could be a sign of kidney disease, diabetes mellitus, liver disease,  tooth abscess, periodontal disease, intestinal problems, cancers of the mouth.

Difficulty going to the toilet – If your cat is straining to go to the toilet, or only passing a small amount of urine, going to the toilet often or licking the genital area frequently these symptoms could be the following;  FLUTD (which is a medical emergency), bladder stones, tumours,  diabetes mellitus, kidney disease or constipation.

Blood in urine (hematuria) – Bladder stones, urinary tract infection, cancer, trauma can all be causes of blood in urine.

Weight loss or gain – There are many causes of weight loss or gain. Weight loss could be caused by diabetes mellitus, hyperthyroidism, malnutrition, kidney failure or any chronic illness.

Pain – Cats are very good at hiding pain from their carers and each cat will have a different pain threshold. There are countless causes of pain in cats, which is why it is important to seek veterinary advice as soon as possible to find out the cause. A cat in pain may be aggressive, withdrawn, hide, or sit with a hunched up appearance.

Discharge – Discharge from the eyes and nose could be indicative of a bacterial or viral infection,  or foreign body. Discharge from the genitals could indicate pyometra.

Ataxia (unsteady gait)  Possible causes include poisoning, neurological disorder,  ear infection, spinal trauma, pelvic fracture, brain trauma.

Abnormal breathing – Heart failure, asthma, lung disease. Panting could be a sign of hyperthermia (heat stroke).

Eyes – Are the pupils both the same size? Shine a light in them, do they become smaller or stay fixed? Either scenario is a medical emergency and could indicate head trauma, seek veterinary attention immediately.

Check the eyes for discharge, this could indicate a foreign body, eye infection or upper respiratory tract infection.

The appearance of the third eyelid (also known as haw) is another indicator that something is wrong with your cat. This could be a sign of dehydration, illness or injury.

Appraising the situation:

Gum colour – The normal colour is pink. Pale to white gums may indicate shock or anaemia. Blue gums indicate not enough oxygen, yellow gums indicate liver problems, bright red can indicate carbon monoxide poisoning or heat stroke.

Dehydration – To check for dehydration grasp some skin at the base of their neck (the scruff) and gently pull it up. In the hydrated cat, the skin will spring back immediately. In a dehydrated cat, the skin will be slower to retract. The more severe the dehydration the slower the skin will take to retract.

Capillary Refill Time (CRT) – This helps you to test your cat’s blood circulation and can indicate dehydration, heart failure or shock. To test capillary refill time lift your cat’s upper lip and press the flat of your finger against the gum tissue. Remove the pressure and you will see a white mark on the gum where your finger was placed. Using a watch with a second hand, time how long it takes for the pink colour to return to the white spot. In the healthy cat, it should take around 1 – 2 seconds to return to pink.


This article has been written to provide a guide to what to look for in regards to signs of sickness, some signs include possible causes. It has not been written by a veterinarian and shouldn’t be used to replace veterinary advice.  This is by no means meant to be for diagnostic purposes, most symptoms of sickness have multiple possible causes, many of which aren’t included in this article.   Therefore it is imperative that you seek proper veterinary attention if you see you suspect your cat is unwell. You should NEVER make a medical diagnosis based on what you read on the Internet, only an examination performed by a qualified veterinarian can give you a definite diagnosis so please if you believe your cat is unwell, seek proper medical care immediately.