Petriage Clinical Insights

IMPORTANT: This article, which is provided for educational purposes only, is based on published veterinary data and decades of work with pets and pet parents. The information provided here is not designed to be comprehensive but to help you avoid the pitfalls of online misinformation and most importantly, to frame the conversation you should have with your veterinarian. Your veterinarian’s perspective may differ from what is expressed here. Always consult with your veterinarian.

Enlarged Lymph Nodes (Lymphadenopathy)

Lymph nodes are small glands spread throughout the body, and are an important part of the immune system. They act as a filter for the circulatory system as well as storage for the white blood cells which fight infection. Swollen lymph nodes can be a red flag indicating that your pet’s immune system is hard at work. There are various causes for enlargement, such as allergies, bacterial or viral infections, and a few types of cancer. 


There are a few places where you might be able to detect swollen lymph nodes that are close to the surface. Look for any nodules beneath the base of the jaw, in front of the shoulder, deep in the two armpits, and on the back of the hind leg, just above the knee.


Lymphadenopathy is a significant finding. Do not ignore it even if your pet is acting 100% normal. You should make an appointment with your vet promptly to determine the possible cause and significance of the enlargement.


  • Lymph nodes reside well below the surface of the skin, and are firm to the touch, especially when inflamed. 
  • If you think you feel an enlarged lymph node, try to determine the size of the node on the other side. Nodes are symmetrical, and palpating the other side can help you determine what might be normal.
  • Try to ascertain the size of other lymph nodes in other locations to see if enlargement is general or localized. 
  • Do not despair if you are not able to find the nodes in other locations. Normal lymph nodes can be difficult or impossible to find even for a trained professional. 
  • If you suspect enlarged lymph nodes, take some time to collect the last few years of your pet’s travel history. Your veterinarian will need this information to diagnose the cause of the lymphadenopathy.
  • Make sure to inform your veterinarian of any exposure to ticks.