What Causes Swollen Lymph Nodes in Dogs?

swollen lymph nodes in dogs_canna-pet

There are many reasons your dog could have swollen lymph nodes. The most common assumption and fear is that your dog has Lymphoma, which is a quite serious diagnosis. And while this is a possibility, there are several other common health problems that could be causing these swollen glands in your dog.

Inflamed lymph nodes are referred to as Lymphadenitis, which is the enlarged of lymph nodes from either an infection or inflammation in dogs. An infection can arise from either a bacterial or fungal infection, which are both treatable and curable illnesses.

In contrast, inflammation occurs most commonly when your dog has a tissue reaction to an injury. This could be caused from a number of injuries including splinters and surface abrasion.

Bacterial and Fungal Infections

The most common type of bacterial infection in dogs is Streptococcal, or Strep throat. While the bacteria can become infected in the intestines, urinary, and genital tract, most commonly dogs get Streptococcal in their respiratory system. Typically, the lymph nodes in dog’s throats become most swollen during this type of bacterial infection.

causes of swollen lymph nodes in dogs

Dogs have comparable Strep throat symptoms to human infections including difficulty swallowing, coughing, fever, pain and lethargy. A similar course of treatment can also be taken which includes antibiotics and plenty of fluids.

Although curable, Strep throat can be incredibly painful for your dog so it’s important to try your best to keep them protected from the infection. Avoiding uncleanly areas with a lot of dogs can help decrease the chances of getting this bacterial infection, however there’s no sure way to avoid contraption.

Younger dogs tend to get the infection more easily because their immune systems are still developing. In contrast, older dogs commonly get Strep as their immune systems start to deteriorate.

There are several other types of bacterial and fungal infections that your dog can contract with very similar symptoms. Therefore, it is important to take your dog to the vet when you notice unusual behavior. The vet will be able to run a series of tests depending on the severity of the infection including blood work, urine samples, and lymph node aspiration (liquid) can be examined under a microscope.
infections that cause swollen lymph nodes in dogs

Canine Cancer: Lymphoma

As mentioned earlier, Lymphoma typically causes swollen lymph nodes in the throat because this is where the cancer originates. If the cancer doesn’t form in the throat’s lymph nodes the cancerous cells will typically house themself in the spleen or bone marrow.

Malignant lymphoma is the most common type of tumor in dogs. The cancer is generally seen in middle aged to older dogs, approximately six to nine years old. Breeds that are believed to be more susceptible and have higher incidence rates of lymphoma are Boxers, Bullmastiffs, Basset Hounds, Saint Bernards, Scottish Terriers, Airedale Terriers, and Bulldogs. Dogs with lower risks include Dachshunds and Pomeranians, with neutered females tending to have a better prognosis.

swollen lymph nodes from lymphoma in dogs

The main distinction between a bacterial or fungal infection and lymphoma is that despite the lymph nodes being swollen, lymphoma is usually painless and most dogs do not show any distinctive signs of illness. In certain cases, dogs can lose weight, have difficult breathing, become overly thirsty, have a fever, or display inflammation of the whole body.

So while bacterial and fungal infections are seen to enlarge lymph nodes, they are accompanied by a series of different symptoms than cancer in dogs.

Treatment of Lymphoma varies depending on the stage of the disease. Without any sort of treatment, the disease can take over a dog’s body in four to six weeks. Thus, systemic chemotherapy, or surgical removal is necessary to elongate your dog’s life after a diagnosis of Lymphoma.

Conventional chemotherapy results in total remission proximately 60-90% of the time with an average survival time of 6-12 months. In approximately 20-25% of cases, dogs will live two years or longer after initiation of treatment. If the cancer reoccurs and a second round of treatment is taken, the median survival rate is approximately one year.

symptoms of lymphoma in dogs

While the prognosis of this disease is quite shocking and stressful to receive, the most important thing is to keep your dog comfortable in his latter stages of life. But it’s also important to remember that there are several other instances that result in swollen lymph nodes. Seeking medical attention should be the first step in getting your dog on the road to recovery, whatever the cause may be.


  1. Clark, Mike. “Swollen Lymph Nodes In Dogs: Symptoms, Causes, & Treatments.” Dogtime, 31 Jan. 2018, Accessed 29 Sep. 2017. www.dogtime.com/dog-health/56305-swollen-lymph-nodes-dogs-symptoms-causes-treatments.
  2. “Lymph Node Inflammation (Lymphadenopathy) in Dogs.” PetMD, Accessed 29 Sep. 2017. www.petmd.com/dog/conditions/cancer/c_multi_lymphadenopathy.
  3. “Lymph Node Inflammation (Lymphadenopathy) in Dogs – Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost.” WagWalking, 28 May 2016, Accessed 29 Sep. 2017. www.wagwalking.com/condition/lymph-node-inflammation-lymphadenopathy.
  4. “Enlarged Lymph Nodes in Dogs.” VetInfo, Accessed 29 Sep. 2017. www.vetinfo.com/enlarged-lymph-nodes-in-dogs.html.
  5. Burke, Anna. “Lymphoma in Dogs: Symptoms, Diagnosis, and Treatment.” American Kennel Club, 3 Nov. 2016, Accessed 29 Sep. 2017. www.akc.org/expert-advice/health/lymphoma-in-dogs-symptoms-diagnosis-and-treatment/.

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