My Dog’s Paws Are Swollen - Causes and Treatment

The causes that can cause the swelling of the paws and limbs of dogs are varied and can be related to different organs, devices and systems. In this first section, we collect the main causes of swollen paws in dogs.

Edema

Edema is a pathological accumulation of fluid in the interstitial space and in organic cavities (e.g., in the abdomen or thorax). When edema occurs at the level of the extremities, it is called peripheral edema. Generally, swelling begins in the distal region of the limb (i.e., the area farthest from the animal's trunk) and progressively spreads toward the proximal region (the area closest to the animal's trunk).

The causes that can cause edema are numerous and can affect different organs. Below, we describe the most important ones:

• Right heart failure: it can occur in pulmonary stenosis, interventricular communication, pericardiopathies, etc. When the right side of the heart does not function properly, blood backs up in the venous system, increasing hydrostatic pressure and favoring the outflow of fluid from inside the blood vessels toward the interstitium, causing edema. In addition, in this situation, the renin-angiotensin-aldosterone axis is activated, favoring the retention of water and sodium and increasing the occurrence of edema.
  
  
• Liver failure: when the liver is not functioning properly, it cannot synthesize enough albumin, so the level of this protein in the blood decreases (hypoalbuminemia). As a result, oncotic pressure decreases, which promotes the outflow of fluid from inside the blood vessels into the interstitial space, leading to edema.
  
  
• Nephrotic syndrome: When the permeability of the renal glomeruli is altered, proteins are released into the interstitial space. Albumin, in particular, is released because it is the smallest protein. As a result, there is hypoalbuminemia, a decrease in oncotic pressure, and eventually edema in the interstitial space.
  
  
• Malnutrition: in malnourished dogs or in a diet that does not provide an adequate amount of protein, there is a decrease in plasma proteins (hypoproteinemia), which is manifested by a decrease in oncotic pressure and the appearance of edema.
  
  
• Digestive diseases: Both pathologies that lead to decreased absorption of proteins in the intestine and pathologies that lead to loss of proteins through the digestive tract can cause a decrease in plasma proteins. This disease, called hypoproteinemia leads to a decrease in oncotic pressure and the appearance of edema.
  
  
• Alteration of vascular walls: When the endothelial cells that form the walls of blood vessels are injured, there is an outflow of fluid from inside the vessels into the interstitium, causing edema. This change in blood vessel walls can be caused by chemical irritants, bacterial toxins, viruses, reptile venoms (especially snakes), and anoxia (lack of blood flow to an area).

Lymphedema

Lymphedema is defined as an accumulation of fluid in the intercellular space due to a malfunction of the lymphatic system. It may be caused by congenital abnormalities that affect the lymphatic system or may occur secondary to other pathologic processes such as neoplasms, inflammation, trauma, or infection.

The main clinical sign of lymphedema is swelling of the affected area. As with edema, the swelling begins in the distal portion of the limb or paws and spreads to the proximal portion as it progresses. Specifically, in dogs, the hind limbs and paws are more commonly affected.

Arthritis

Arthritis is an inflammatory process that affects the joints, especially the articular cartilage and synovial membrane. Arthritis can be caused by pathogenic microorganisms (such as bacteria and mycoplasma) or have a non-infectious origin, as is the case with rheumatoid arthritis or immune-mediated arthritis associated with chronic inflammation, leishmaniasis, or neoplasia.

In arthritis, thickening or swelling is observed only at the level of the affected joint, unlike in cases of edema or lymphedema, in which the swelling gradually spreads throughout the body. In addition, arthritis usually presents with other clinical signs such as limping, abnormal gait, heat, and pain on palpation.

If you want to learn more about arthritis in dogs, do not hesitate to take a look at this other article we recommend.

Allergic reactions

Allergic reactions caused by the sting of some insects (such as bees, wasps, or spiders), as well as allergies to certain medications (especially vaccines), can cause inflammation and swelling of the face and body, including the extremities. In these cases, the swelling is often accompanied by itching, redness of the skin and papules.

Developmental diseases

There are some diseases of skeletal development that can cause thickening of the extremities. One of the most important is metaphyseal osteopathy, also called hypertrophic osteodystrophy.

It is a pathology that mainly affects puppies of large breeds, such as Weimaraners or Great Danes, between 3 and 7 months of age. It is usually associated with inadequate feeding of the puppies (due to overfeeding, excess protein or calcium), although it also seems to be related to quadrivalent vaccination and distemper virus infections. It usually involves the metaphyses of the long bones such as the ulna/radius or tibia. In addition to the swelling at the level of the bone metaphyses, pain, fever, and anorexia may be observed.

Bone tumors

In dogs, bone tumors can be divided into two major groups:

• Primary bone tumors: are those that originate in the bone itself. Osteosarcomas are the most common, but fibrosarcomas, chondromas and chondrosarcomas can also be seen.
  
  
• Secondary or metastatic bone tumors: are those that arise from metastases of malignant tumors in other parts of the body. In dogs, the most common tumors that metastasize to bone are carcinomas of the mammary gland, liver, lung, and prostate.

Regardless of the specific type of bone tumor, swelling around the affected bone and varying degrees of lameness may occur.

At this point we must mention a pathology that does not have a tumor origin, but is very similar to a tumor. It is hypertrophic osteopathy, a disease in which there is a proliferation of the outermost layer of bone (periosteum). It usually occurs in response to pathology in another region of the body (e.g., lung tumors, granulomas, or dirofilariosis), although its pathogenesis is not entirely clear. The good news is that the bone lesions disappear once the primary cause is removed.

Inflammatory processes

Inflammatory processes at the level of the soft tissues of the extremities can lead to focal swelling. Unlike other processes in which more extensive or generalized thickening occurs, a well-defined nodular swelling is observed in these cases.

Depending on the chronicity of the inflammatory process, we can make a distinction:

• Abscesses: in acute inflammation due to bacterial infections.
  
  
• Pyogranulomas: in subacute inflammations caused by foreign bodies (such as spines).
  
  
• Granulomas: in chronic inflammatory processes caused by fungi or parasites.

Similarly, trauma from falls, blows, being run over, or dog fights can cause swelling of the extremities due to the inflammatory process resulting from the trauma. When these traumas result in a fracture, the inflammation of the soft tissues surrounding the broken bone is even more noticeable.

In the first part of this article, we talked in general about the different causes that can cause swelling on the paws and legs of dogs. However, swelling occurs and develops differently in each process. In this way:

• In the case of edema or lymphedema: it is common that more than one limb is affected. In these cases, the swelling starts in the distal part of the extremities (the part farthest from the trunk) and progresses to the proximal part (the part closest to the trunk). In addition, it is characteristic that when a finger is pressed firmly on the affected tissue, an indentation (called a dimple) is formed that persists for several seconds after the finger is removed.
  
  
• In the case of bone tumors, trauma and fractures: only swelling is observed in the affected paw.
  
  
• In the case of arthritis: swelling is limited only to the affected joint. Similarly, in developmental diseases such as metaphyseal osteopathy, the swelling is seen only at the level of the affected metaphysis.
  
  
• In the case of local inflammatory processes: such as abscesses, granulomas, or pyogranulomas, a nodule-like swelling is observed. In addition, depending on the cause of the swelling, very different symptoms can be observed, associated with different organs and systems. It is important to consider the clinical signs of the animal to make the diagnosis and determine the most appropriate treatment.

Unfortunately, many of the causes that can lead to swollen paws in dogs, such as tumors, allergies or immune-mediated processes, cannot be prevented. However, there are other pathologies associated with this sign that can be avoided through a series of preventive measures:

• Adhere to the vaccination and deworming schedule: This simple preventive measure can avoid all infectious and parasitic causes that can be associated with the appearance of swollen paws in dogs.
  
  
• Offer an appropriate diet: As we have already explained, malnutrition can cause edema and therefore swelling of the limbs and paws. Conversely, malnutrition in puppies can lead to developmental diseases that also cause this kind of swelling. Therefore, it is important to provide a balanced diet that meets the needs of each animal.
  
  
• Routine veterinary examinations: through routine examinations, it is possible to detect some of the pathologies described in this article at an early stage, even before they cause swelling of the limbs. Early diagnosis of these pathologies allows appropriate treatment and prevents the appearance of these and other clinical signs.

As we have explained in this article, there are numerous causes that can cause paw swelling in dogs. Some of them are associated with mild and transient processes that resolve spontaneously or with symptomatic treatment.

However, other processes can become serious and endanger the life of the animal. Therefore, if you notice that your dog has swollen paws and he or she is limping, it is important that you go to your trusted veterinarian. With a proper diagnostic protocol, you will be able to determine the cause of this change and establish a treatment for swollen paws that is appropriate to the cause.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

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