What this means
Yellowing is easiest to see where there is no fur: the gums, the whites of the eyes, the inside of the ears and sometimes the skin. The gums may look pale lemon, mustard or orange. It shows better in daylight than under a lamp, and in a cat with pigmented gums the colour is worth judging from the whites of the eyes as well. If in doubt, compare with an older photo in which your cat's eyes or gums are visible.
Yellowing is a sign rather than a disease, and different causes can lie behind it. Sometimes the problem is in the liver itself, sometimes the bile ducts are blocked or inflamed, and sometimes red blood cells break down faster than the liver can handle them. In cats it matters in particular that liver trouble can also develop when a cat eats very little for a few days, so a cat that is yellow and not eating is more urgent. Telling the causes apart takes blood tests and an examination.
Your vet will find it useful to know when you first noticed the yellow colour, whether your cat is eating, whether it is vomiting, whether the colour of the urine and stools has changed and whether it could have swallowed something toxic. If you can, photograph the gums and eyes so the change over time can be seen. Do not wait and do not try to guess at home.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your cat.
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Red blood cells breaking down
When cells break down too fast the liver cannot process their pigment and it builds up in the blood. The cat is dull and the gums may be pale as well.
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Liver disease
When liver cells are damaged, bile pigment is cleared less well. The cat may eat less, vomit or be apathetic.
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Problems with the gallbladder or bile ducts
If bile cannot flow freely it backs up into the blood. Belly pain, vomiting and refusing food may go with it.
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The immune system destroying blood cells
When the body attacks its own red blood cells they break down too fast. The cat tires quickly and looks pale and yellow.
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Poisons or other harmful substances
Some toxic substances can damage the liver or the blood cells. It matters to say if your cat could have swallowed something toxic.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Where and when you first saw the yellow tint: gums, eyes or ears
- Whether your cat is eating and drinking or has stopped eating
- Whether it is vomiting
- Whether the urine has changed colour, for example dark orange
- Whether the stools have become very pale
- Whether your cat is dull, pale or tires quickly
When to book a routine visit
Yellow gums or eyes are always a reason to see a vet promptly, as soon as possible, rather than wait to see whether it passes. Say when you noticed the yellow colour, whether your cat is eating and what else you have seen.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Feline infectious peritonitis (FIP) Infections A severe disease that develops when the coronavirus living in cats' guts changes inside a cat's body and starts spreading throughout it. It inflames blood vessels and organs, and fluid can collect in the belly or chest.
- Pyruvate kinase deficiency Blood and immunity An inherited disease in which the red blood cells lack an enzyme they need to make energy. These cells break down sooner than they should, so the cat can develop anaemia.
Body systems: Infections Blood and immunity