What this means
Lymph nodes filter the lymph and help the body fight disease. They can swell when there is inflammation or infection nearby, when they react to illness elsewhere in the body, or when abnormal cells multiply inside them. The ones that can be felt in a cat are usually under the jaw, in front of the shoulders, in the armpits, in the groin and behind the knees. In a healthy cat they are so small that they usually cannot be felt at all.
Swollen lymph nodes are a sign, not a diagnosis. A single enlarged node near a wound or a sore tooth may mean local inflammation, while several enlarged nodes in different places point to a cause that has to be looked for more widely. Neither size nor firmness tells you what it is, so it cannot be judged by touch.
Cats hide pain and illness, so alongside the swollen nodes it matters to notice other changes: whether your cat is losing weight, eating as usual, quieter than normal or breathing differently. A small shift, such as sleeping longer or playing less, is information, not nothing.
Possible causes
These are things that can cause this sign. It is not a diagnosis, and they are not equally likely for your cat.
-
Inflammation or infection nearby
A wound, an abscess, a problem with the teeth or gums or a skin infection can make the closest node swell. A vet needs to find what set it off.
-
Infection throughout the body
When the body is fighting a wider infection, lymph nodes can swell in several places at once. The cat is often listless and eats less.
-
Lymphoma
This is a cancer of the lymph cells that can enlarge one or several nodes. Weight loss, a poor appetite or laboured breathing may go with it.
About the condition: Lymphoma -
Another cancer that has spread to the node
Some growths spread through the lymph nodes, so a swollen node can be the first sign you see. Only a vet, with tests, can tell.
-
Inflammation driven by the immune system
Sometimes nodes swell because the immune system is overreacting. There may also be changes in the skin, joints or other organs.
-
Another illness you cannot recognise from outside
Many illnesses can change the lymph nodes, and they cannot be told apart by looking or feeling. That is why a cat that otherwise looks well still needs to be examined.
What else to watch for
These observations help your vet build the picture faster. Note down what you saw and when.
- Where you feel the lump, and whether there is more than one
- Whether your cat is losing weight or eating less
- Whether your cat is quieter, sleeping more or hiding
- Whether there is any vomiting or diarrhoea
- Whether breathing has become harder or the chest moves with effort
- Whether there is a wound, a bite mark or bad teeth nearby
When to book a routine visit
Have a vet check any new swollen lymph node, because its cause cannot be told from outside. If your cat also loses weight, is lethargic, is not eating or has laboured breathing, go promptly, as soon as you can. If it breathes with an open mouth, go immediately.
Related conditions
Conditions whose entries mention this sign. The list is somewhere to read on, not a way to reach a diagnosis.
- Feline immunodeficiency virus (FIV) Infections A virus that slowly weakens a cat's immune system, so the body finds it harder and harder to fight off other infections. An infected cat can look perfectly healthy for a long time, even for years.
- Feline leukaemia virus (FeLV) Infections A virus that spreads between cats through saliva and can cause anaemia and lymphoma and weaken the immune system. Not every infected cat falls ill, but a cat in which the virus takes hold faces serious disease.
- Lymphoma Cancer A cancer that arises from lymphocytes, the white blood cells that defend the body against disease. Because these cells are found throughout the body, lymphoma can affect the gut, the lymph nodes, the chest, the kidneys or other organs.
Body systems: Infections Cancer