No one likes to find a swelling or lump on their cat. When these swellings are lymph nodes, we often think of the worst case scenario: cancer.
While it is certainly a significant cause of swollen lymph nodes, cancer is not the only reason for swollen lymph nodes in cats.
Here we'll look at what swollen lymph nodes are, why you might notice them, and what you should do about it.
Key takeaways
- Swollen lymph nodes in cats (lymphadenopathy) are usually a sign that the immune system is responding to infection, inflammation, or, less commonly, cancer.
- Common causes include infections (such as FeLV or FIV), dental disease, and immune responses to vaccines or other conditions.
- Although not usually an emergency, any unexplained lymph node swelling should be evaluated by a veterinarian, especially if your cat is showing signs such as lethargy, difficulty breathing, or loss of appetite.
What are swollen lymph nodes in cats?
Lymph nodes are an important part of the feline immune system. They are found throughout the body, with clusters located in certain areas, such as the neck or armpits.
Lymph nodes are bean-shaped structures that filter fluid called lymph. They help recognize and eliminate pathogens (foreign invaders like bacteria or viruses) as well as abnormal cells, including cancer cells. White blood cells in the lymph and lymph nodes play a key role in fighting infections.
When something activates the immune system, lymph nodes can swell as they filter out harmful invaders or abnormal cells.
The medical term for swollen lymph nodes is lymphadenopathy. This may refer to a single enlarged lymph node or multiple swollen lymph nodes.
The swelling itself is usually not painful, but the underlying condition causing the lymphadenopathy may be uncomfortable.
Causes of Swollen Lymph Nodes in Cats
Swollen lymph nodes in cats are generally associated with three main causes:
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Reactive hyperplasia: When antigens (markers of foreign invaders) arrive from the tissue draining from a specific lymph node, the lymph node may enlarge because it produces more white blood cells to handle the problem. This can happen with dental disease, infections near the lymph nodes, recent vaccination, or autoimmune diseases.
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Lymphadenitis: This is a direct inflammation of the lymph node itself, often due to infection. Examples of causes include feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and fungal infections such as histoplasmosis. Affected lymph nodes may be warm to the touch, swollen and painful.
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Cancer: Some cancers, such as lymphoma, can cause enlarged lymph nodes (although this form is less common in cats than gastrointestinal lymphoma). Lymph nodes can also enlarge if cancer spreads there.
Rarely, other problems, such as local edema (excess fluid trapped in tissues), may mimic or contribute to swollen lymph nodes in cats.
Are Swollen Lymph Nodes in Cats an Emergency?
Swollen lymph nodes in cats are not usually an emergency, but you should contact your veterinarian for an evaluation if you notice enlargement.
However, swollen lymph nodes may be associated with more serious conditions.
Seek emergency care if your cat:
When to Call Your Vet About Cat's Swollen Lymph Nodes
If you notice a swollen lymph node on your cat, it's always a good idea to contact your veterinarian.
If your cat has recently been vaccinated, is young, or has a likely explanation for swollen lymph nodes (such as a recent dental procedure), your veterinarian may recommend home monitoring.
If there is no clear cause, your veterinarian will want to examine your cat to determine the reason for the swelling.
Again, if you notice any of the following signs in addition to swollen glands, seek veterinary care promptly:
How Vets Diagnose Cat's Swollen Lymph Nodes
Your veterinarian will start by palpating (feeling) the external lymph nodes, also called peripheral lymph nodes, to see if they are enlarged.
These are located:
A common diagnostic step is to take a sample of cells from the lymph nodes using a needle (fine needle aspiration or FNA) and examine them under a microscope (cytology).
In some cases, this is done by the veterinarian in his clinic; other times, the samples are sent to a veterinary pathologist for evaluation.
Additional tests may include:
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Blood test: To assess infection, anemia and organ function
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Imaging: X-rays, ultrasound or other imaging to check for infection or cancer
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Fungal tests or culture: If an infection is suspected, the veterinarian may recommend fungal testing or culture to determine what type of infection is present and which antifungals or antibiotics will be effective for treatment.
If the cause remains unclear or if the lymph node is inside the body and cannot be reached safely with a needle, a surgical biopsy may be necessary. This may involve removing part or all of the lymph node and sending the sample to a pathologist for evaluation.
Treatment of Swollen Lymph Nodes in Cats
Treatment depends on the underlying cause.
For example:
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Fungal infections (eg, histoplasmosis) may require long-term antifungal medications like itraconazole.
Recovery and Management of Swollen Cat Lymph Nodes
Recovery and management vary greatly depending on the cause of swollen lymph nodes.
Your veterinarian will guide you based on your cat's diagnosis.
Prevention of Swollen Lymph Nodes in Cats
Not all causes of swollen lymph nodes in cats are preventable, but you can reduce the risk by:
FAQs About Swollen Lymph Nodes in Cats
Is swollen lymph nodes in cats serious?
Not always. Lymph nodes may swell due to minor problems like a recent vaccination or dental disease. However, unexplained lymph node swelling should be evaluated by a veterinarian.
What is the most common cause of swollen lymph nodes?
Infection is the most common cause of swollen lymph nodes in cats.
How to check a cat's lymph nodes?
You may be able to feel lymph nodes under your jaw, in front of your shoulder blade, and behind your knees. They are normally very small, often the size of a pea. Your veterinarian will be the best source for determining whether your cat's lymph nodes are enlarged.
