Updated September 24, 2019

Lymph nodes are organs found throughout the body that play a key role in the body’s immune response to foreign invaders. When lymph nodes are inflamed due to illness, they increase in size and can be tender to the touch. Lymphadenopathy is the medical term for enlarged or swollen lymph nodes.

What causes swollen lymph nodes in cats?

Lymphadenopathy can occur due to any illness, be it severe or minor, in humans and cats alike. However, lymphadenopathy in cats is much more common due to severe illness.

Generally, cats with lymphadenopathy feel poorly. They will likely be lethargic and depressed with decreased appetites. If the lymph nodes in the neck are enlarged, swallowing may be painful and will also affect your cat’s appetite.

While you may not notice enlarged lymph nodes, your vet will. Lymph nodes are present throughout the body, but peripheral nodes can be felt in the neck, in front of the shoulder, and behind both knees.

Lymphadenopathy can occur in response to any illness, including:

  • Viral disease, such as feline immunodeficiency virus (FIV) and feline leukemia (FeLV)
  • Bacterial disease, such as bartonellosis (Cat Scratch Fever) and tularemia
  • Cancers, such as leukemia or lymphoma
  • Protozoal disease, including toxoplasmosis, hepatozoonosis, and cytauxzoonosis
  • Fugal disease, such as blastomycosis, cryptococcal infection, and histoplasmosis
  • Immune-mediated, as is the case with eosinophilic reactions

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Diagnosing your cat's swollen lymph nodes

Lymphadenopathy itself tells your cat’s veterinarian that he is likely battling a serious illness. Diagnostic tests will be run to determine the underlying cause of lymph node enlargement. A full chemistry and complete blood count (CBC) will be run to check major organ function as well as look for abnormalities in the number of red and white blood cells. FIV and FeLV tests can be run in house as well. Luckily these tests can all be covered by cat insurance. 

If routine blood tests give no insight into what may be causing your cat’s enlarged lymph nodes, your veterinarian may suggest a lymph node aspirate. A needle can be used to obtain cells directly from your pet’s lymph node. These cells can be viewed under a microscope by a pathologist and may show infective organisms or cancer cells, thereby giving your veterinarian an underlying cause for your pet’s enlarged lymph nodes.

There is no specific treatment for lymphadenopathy, as it is a symptom of disease and not a disease itself. Lymphadenopathy will resolve when the underlying cause is also resolved.

In cats, lymphadenopathy can be very subtle and easy to miss. If you notice signs of illness in your cat or if you feel enlarged lymph nodes, schedule an appointment with his veterinarian right away.

Jan 21, 2014

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