Most people are familiar with the swelling that can occur in a person's lymph nodes during an infection, but what about swollen lymph nodes in dogs? Unfortunately, there are several potential causes for this condition in our canine companions, including everything from infections to cancer. Swollen or enlarged lymph nodes are also termed lymphadenopathy. In this blog post, we will take a look at some of the most common causes of swollen or enlarged lymph nodes in dogs so that you can better understand what might be causing this. Thanks for reading!
Where are lymph nodes located on dogs?
Lymph nodes are glands of the lymphatic system. The lymphatic system is a network of tubes and vessels that help rid the body of toxins, waste, and other unwanted material. Lymph nodes are located throughout the lymphatic system, including in the neck, chest, abdomen, and legs.
When it comes to the physical examination, your veterinarian will evaluate and palpable all the peripheral lymph nodes. The peripheral lymph nodes are submandibular (beneath the jaw area), prescapular (lower neck, near the chest), axillary (armpit), inguinal/femoral (inner thigh), and popliteal (behind the knees).
Canine lymph node location chart
What do swollen lymph nodes look like on dogs?
Swollen lymph nodes can vary in size, but they are typically larger than normal and may feel firm or rubbery to the touch. In some cases, the nodes may be so large that they are visible on the surface of the skin. In other cases, your dog may have swollen lymph nodes that cannot be seen or felt as they are not involving the peripheral lymph nodes as discussed above.
The most commonly identified swollen lymph nodes in dogs by dog owners are the submandibular lymph nodes. These are the lymph nodes located beneath the jaw and are often the most recognizable because their location makes them easy to see and feel.
What causes swollen lymph nodes in dogs?
There are several potential causes of swollen lymph nodes in dogs and in most cases, enlarged or swollen lymph nodes are a result of an infectious or cancerous process.
Infectious causes of swollen lymph nodes in dogs
One of the most common causes of swollen lymph nodes in dogs is due to an infection within the body. Infections may be within the lymph node itself or be a reactive lymph node (reactive lymphadenopathy) from a distant source. There are several possible infectious causes of enlarged lymph nodes, including but not limited to bacterial, tick-borne, fungal, and parasitic. Many dogs who have one of these infections will also have other symptoms such as fever, lethargy, or diarrhea.
In severe cases, dermatological infections, such as pyoderma can result in swollen lymph nodes in dogs. The affected lymph nodes are often near the site of the infection.
Cancerous causes of swollen lymph nodes in dogs
Lymphoma is the most common cancer that affects lymph nodes in dogs and it can be difficult to tell apart from other infections without running some diagnostic tests. Lymphoma is a type of cancer that originates in the cells of the lymphatic system and can spread to other parts of the body.
Dogs with lymphoma may have enlarged lymph nodes that are not associated with any other symptoms. In some cases, dogs with lymphoma may also have weight loss, appetite changes, and fever.
Metastatic cancers, or cancers that have spread from another area of the body, can also cause swollen lymph nodes.
Other causes of swollen lymph nodes in dogs
There are a few other potential causes of swollen lymph nodes in dogs that are not associated with an infection or cancer. These include but are not limited to:
- Autoimmune disease: In some cases, the body's immune system may mistakenly attack healthy tissue, resulting in swollen lymph nodes.
- Allergies: Dogs with severe allergies may have swollen lymph nodes as a result of the allergic reaction. Allergies are often accompanied by other symptoms such as itchy skin, red eyes, and sneezing.
- Trauma: Physical trauma to the lymph node area may result in swollen lymph nodes.
Diagnosing swollen lymph nodes in dogs
To determine the cause of swollen lymph nodes in your dog, your veterinarian will start with a thorough history and physical examination. This will help to rule out any possible causes and narrow down the potential list of differential diagnoses.
Your veterinarian will feel the lymph nodes in question and may also palpate (feel) other areas of the body for swollen lymph nodes that are not visible on the surface.
After the physical examination, your veterinarian will likely recommend some diagnostic tests to confirm or rule out a diagnosis. These tests may include:
- Complete blood count (CBC): This test will evaluate the number and types of white blood cells and can help to rule out an infection or cancer. The CBC can also evaluate for anemia.
- Biochemical profile: This is a basic blood test that measures organ function and can also help to rule out an infection or cancer.
- Urinalysis: This test will evaluate the urine for any abnormal cells or substances that may be indicative of an underlying condition.
- Lymph node aspirate: In this procedure, a needle is inserted into the swollen lymph node and a small amount of material is withdrawn (aspirated) for evaluation. The fluid will be examined for the presence of cancer cells, bacteria, or other abnormal cells.
- Biopsy: A biopsy is the removal of a small piece of tissue from the swollen lymph node for evaluation. This is the most definitive way to diagnose swollen lymph nodes and rule out cancer.
- X-rays: X-rays may be recommended in some cases to check for any changes in the size or shape of the lymph nodes. X-rays are also beneficial in attempting to determine why the lymph nodes may be enlarged.
- Ultrasound: Abdominal ultrasound may also be used in some cases to evaluate the lymph nodes for any abnormal changes.
Treatment for swollen lymph nodes in dogs
The treatment for swollen lymph nodes in dogs will depend on the underlying cause.
For example, if the swollen lymph nodes are due to an infection, the infection will need to be treated with antibiotics. If the swollen lymph nodes are due to cancer, more aggressive treatment options such as chemotherapy or radiation therapy may be recommended.
In some cases, the mildly swollen lymph nodes may resolve on their own without any treatment. However, it is important to have your dog seen by a veterinarian so that the cause can be determined and appropriate treatment can be initiated, if necessary.
Frequently asked questions about swollen lymph nodes in dogs
Are swollen lymph nodes in dogs painful?
Swollen lymph nodes are not usually painful. However, if the swollen lymph nodes themselves are infected, they will typically be painful and uncomfortable.
What is the prognosis for dogs with swollen lymph nodes?
The prognosis for dogs with swollen lymph nodes will depend on the underlying cause. Many conditions that cause swollen lymph nodes are treatable and have a good prognosis. However, some conditions such as cancer can be more serious and have a poorer prognosis.
It is important to have your dog seen by a veterinarian so that the cause of the swollen lymph nodes can be determined and appropriate treatment can be initiated.
Do swollen or enlarged lymph nodes always mean cancer for dogs?
No, swollen or enlarged lymph nodes do not always mean cancer for dogs. There are many potential causes of swollen lymph nodes in dogs, including infections and other conditions. However, swollen lymph nodes can also be indicative of cancer, so it is important to have your dog seen by a veterinarian so that the cause can be determined.
In conclusion, swollen lymph nodes in dogs or lymphadenopathy can be caused by a variety of things, ranging from infections to cancer. It is important to have your dog seen by a veterinarian so that the cause can be determined and appropriate treatment can be initiated. A thorough investigative diagnostic process will isolate the exact cause of the swollen lymph nodes and a treatment plan can be implemented. If you have any questions or concerns about swollen lymph nodes in your dog, please do not hesitate to speak with your veterinarian.