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How Dangerous are Swollen Lymph Nodes in Dogs?

Written by: Dogster Team

Last Updated on February 1, 2024 by Dogster Team

Allergic reaction on back hind rear leg of brown brindle dog

How Dangerous are Swollen Lymph Nodes in Dogs?

My five-year-old female beagle has a swollen lymph
node under her front leg. Should I get it checked
out or just wait and see?

Lowell, MA

I’ll answer your question in a moment. But first let’s discuss lymph nodes.

Lymph nodes are part of the immune system. They consist of immune cells surrounded by a capsule. Lymph nodes are located throughout the body. Some of the most noticeable ones are located under the ears, in front of the shoulders, and behind the knees.

Anything that activates the immune system can cause a lymph node to swell. In many cases, this is normal and no cause for concern. For instance, as I discussed in a previous post, vaccines often lead to swollen lymph nodes. As well, any sort of trauma or infection can cause enlargement of the nearest node. An infected tooth may cause the node under the ear to swell. A torn toenail may cause the node behind the knee to swell.

Unfortunately, there are more nefarious causes of swollen lymph nodes. Several types of cancer can cause one or more nodes to enlarge. I am happy to say that five-year-old dogs do not develop cancer often. However, other syndromes (such as Lyme disease and certain systemic fungal infections) also can cause swollen nodes.

What I am going to say next probably won’t surprise you. I recommend that you have a vet examine your dog. He or she should be able to confirm that the swollen area is, in fact, a lymph node and not some other type of growth. And, the vet will be able to test the area to determine what is going on. This can be done easily and with minimal pain in most cases using a technique called aspiration.

I doubt that something serious is going on. However, it is definitely better to be safe than to be sorry.

Featured Image Credit: Pegasene, Shutterstock


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