If your dog’s leg has swollen up, it raises an immediate red flag that something is wrong. There can be many causes of a dog’s leg swelling – including temporary health issues that can be resolved, such as a fever or a sprain, and longer-term problems like arthritis and osteosarcoma. We’ve covered the subject of swollen and hot legs in dogs here.

In this guide, we’re going to focus on a more specific health condition in dogs – fluid retention and tissue swelling due to collection of lymph. Sounds complicated? Well, let’s start explaining…

Similar to the human body, the lymphatic system is like the body’s cleansing system in dogs. It contains the lymph nodes and lymph vessels and contains lymphocytes, which are white blood cells that help guard the body against any infections or inflammations. When the blood circulates, this complex process includes the collection and transfer of a clear fluid, called lymph.

Lymph is taken from the body’s tissues and then returned back into the blood via lymphatic vessels. When there is an abnormality in the lymph flow, the fluid collects and swelling occurs. This is when you’ll see a fluid buildup in your dog’s leg. Lymphedema is the common term for this disorder.

A dog limb swelling with fluid accumulation can be the result of lymph nodes (that filter the fluid) or lymph vessels developing atypically. It can also be the result of an underlying condition that has caused an abnormality in the lymphatic system. Underlying disorders can be tumors, surgery, inflammation, or any other disorder that causes the lymph vessels to become blocked, thus inhibiting proper flow.

Lymphedema is the swelling of various tissues in the dog’s body due to fluid retention within the tissues. This is caused by an abnormality in the lymphatic system.

So, what are the symptoms of a dog’s limb swelling with fluid accumulation? In cases of a fluid buildup in a dog’s leg, the symptoms may be visible and instantly obvious, or might show in other, more subtle, ways.

When the lymph fluid is obstructed, it collects in the bodily tissues. As this occurs, swelling that is noticeable on the outside of the body will be a concern to any pet parent. If your dog is showing any of the following signs, you should schedule a visit to your vet.

Symptoms of a dog's leg swollen with fluid can include:

There are different types of disorders similar to, or secondary to, lymphedema that your veterinarian will check for during the examination and testing while your dog’s leg is swollen with fluid.

A few of these types may also be considered a differential diagnosis that the veterinarian will have to rule out before making a definitive diagnosis of this disorder. Types include:

What might be the possible causes of a dog leg swelling?

There are a few different common causes of a dog limb swelling with fluid accumulation, or Lymphedema. Some studies have shown that this disorder is completely idiopathic (primary lymphedema), but it could also be a secondary condition caused by other illnesses or injuries.

Causes can include trauma, including a result of radiation therapy, Neoplasia, infections, heart issues and cancer. Clearly, many of these are serious health conditions that require treatment so it may be that the symptom of a swollen leg in a dog alerts a pet parent to a wider issue.

It’s thought that some breeds of dog are more predisposed to Lymphedema as a primary condition. These breeds include Rottweiler, Labrador Retriever, Great Dane, Borzoi, Poodle and German Shepherd.

The golden rule when it comes to a suspected health condition with our pets – don’t self-diagnose and guess at the issue. If your dog’s leg is swollen with fluid, make an appointment with your veterinarian, who is best placed to conduct the necessary tests and examinations to diagnose the likely causes of any dog leg swelling-related issues.

To reach a diagnosis, the veterinarian will ask questions about the symptoms your dog is displaying and any underlying conditions your pet may have. The vet will then conduct a complete examination and recommend a urinalysis and blood tests. 

The veterinarian may gently press on the swollen area to see how it responds to this; he or she will be looking for ‘spongy’ feeling tissue and looking for the area which is pressed to keep an indention for a short time before returning to normal.

If your veterinarian suspects your dog has lymphedema, either primary or secondary, he or she may take a sample of the swollen tissue and test it to be sure it is lymph fluid in the affected tissue.

The veterinarian may also choose to perform a lymphangiography, which is a dye test, similar to a heart catheterization, where an imaging source can allow the veterinarian to watch the flow of the colored dye throughout the lymphatic system.

Your vet will recommend a course of swollen dog leg treatment, based around what is most effective to combat the underlying health condition that’s been diagnosed. Fluid retention and tissue swelling in canines may, sometimes, subside naturally but more often, treatment for Lymphedema and other closely-related conditions will be needed. That treatment also depends on whether the swelling is caused by a primary or secondary source.

Treatment options may include:

The affected tissue areas can be wrapped in a compression bandage to help reduce the swelling. The veterinarian will demonstrate how to wrap the areas and will show you the amount of pressure that needs to be applied. Heating pads on a low setting and lymphatic massage may also be options to help your pet.

Since lymphedema can only be treated rather than completely cured, the veterinarian may recommend a special diet for your companion. A diet that is healthy can boost the immune system to allow the lymphatic system to do its job more effectively.

Medication to reduce the swelling or an antibiotic may also be prescribed by your veterinarian. Both may be used to help calm the swelling and the fluid buildup in your dog’s leg.

Recovery from issues relating to fluid retention and tissue swelling due to collection of lymph in dogs depends heavily on the cause, and whether there are other underlying disorders, too.

For example, if your dog has been diagnosed with generalized lymphedema, the prognosis is considered ‘guarded’ and must be watched to see if your dog will go into remission.

Since there are many possible causes of secondary lymphedema, recovery depends on the other conditions and how severe your dog’s lymphatic system has been affected. Your veterinarian will give you advice and instructions on how to care for your dog during this time.

Whatever the cause, fluid retention and tissue swelling due to collection of lymph could be a symptom of a serious medical condition. To avoid high vet care expenses, secure pet health insurance today. The sooner you insure your pet, the more protection you’ll have from unexpected vet costs.