Swollen paws in dogs are a frequent reason for consultation in the small animal clinic. The causes that can produce this sign are multiple and can be related to the alteration of various organs, devices or systems. Analyzing the way in which the swelling appears and evolves will help guide the diagnosis and establish the most appropriate treatment.
If you want to know more about swollen paws in dogs, their causes and what to do, join us in the next article on our site, where we also explain the symptoms and how to prevent swelling in your dog's paws.
Causes of swollen paws in dogs
The causes that can lead to swelling of the extremities of dogs are multiple and can be related to different organs, devices and systems. In this first section, we collect the main etiologies of swollen paws in dogs.
Edema
Edema consists of the pathological accumulation of fluid at the level of the interstitial space and organic cavities (such as the abdomen or thorax). When edema occurs at the level of the extremities, it is referred to as peripheral edema. Generally, the swelling begins in the distal part of the limb (that is, in the area farthest from the trunk of the animal) and, as it progresses, it extends towards the proximal (the area closest to the trunk of the animal).
The causes that can cause edema are numerous and can affect various organs. Here are the most important ones:
- Right congestive heart failure: can occur in cases of pulmonary stenosis, ventricular septal defect, pericardiopathies, etc. When the right side of the heart does not work properly, blood accumulates in the venous system, which increases hydrostatic pressure and favors the outflow of fluid from the interior of the blood vessels towards the interstitium, thus appearing edema. In addition, in this situation the renin-angiotensin-aldosterone axis is activated, which favors water and sodium retention and enhances the appearance of oedema.
- Hepatic failure: when the liver is not working properly, is not able to synthesize a sufficient amount of albumin, so the levels of this protein in the blood decrease (hypoalbuminemia). As a consequence, there is a decrease in oncotic pressure, which favors the outflow of fluid from inside the blood vessels to the interstitial space, thus producing edema. If you want to know more about liver failure in dogs: symptoms and treatment, you can read this article on our site that we recommend.
- Nephrotic syndrome: when the permeability of the renal glomeruli is altered, the exit of proteins occurs into the interstitial space Specifically, albumin is released, since it is the smallest protein. As a consequence, hypoalbuminaemia occurs, a decrease in oncotic pressure and, finally, edema in the interstitial space.
- Malnutrition: In malnourished dogs or with deficient diets that do not provide an adequate level of protein, aoccurs. decrease in plasma proteins (hypoproteinemia), which translates into a decrease in oncotic pressure and the appearance of edema. Do not hesitate to take a look at the Care and feeding of a malnourished dog, here.
- Digestive diseases: both pathologies that produce a decrease in the absorption of proteins at the intestinal level (such as intense parasites or malignant tumors), such as pathologies that lead to a loss of protein through the digestive tract (such as Inflammatory Bowel Disease or IBD) cause a decrease in plasma proteins (hypoproteinemia), which leads to a decrease in oncotic pressure and the appearance of oedema.
- Alteration of the vascular walls: When the endothelial cells are injured, which are those that form the walls of the blood vessels, they It produces the exit of liquid from the interior of the vessels towards the interstitium, appearing the edema. This alteration of blood vessel walls can be caused by chemical irritants, bacterial toxins, viruses, reptile venoms (especially snakes) and anoxia (lack of blood supply to an area).
Lymphedema
Lymphedema is defined as the accumulation of fluid in the interstitial space, due to malfunctioning of the lymphatic system It may be caused by abnormalities congenital that affect the lymphatic system, or be secondary to other pathological processes such as neoplasms, inflammation, trauma or infection.
The main clinical sign associated with lymphedema is swelling of the affected area As with edema, the swelling begins in the distal area of the limb and, as it progresses, it extends towards the proximal. In particular, the hind limbs are more frequently affected in dogs.
Discover more information about Lymphedema in dogs: causes, symptoms and treatment in this other article that we suggest.
Arthritis
Arthritis consists of an inflammatory process that affects the joints, specifically the articular cartilage and the synovial membrane. Arthritis can be caused by pathogenic microorganisms (such as bacteria and mycoplasmas) or have a non-infectious origin, as is the case with rheumatoid arthritis or associated immune-mediated arthritis to chronic inflammation, leishmaniasis or neoplasms.
Unlike in cases of edema or lymphedema, in which you see a swelling that spreads progressively throughout the extremity, in the case of arthritis you only see a thickening orswelling at the level of the affected joint In addition, other clinical signs such as limping, abnormal gait, heat and pain on palpation usually appear in cases of arthritis.
If you want to know more about Arthritis in dogs: clinical signs and treatment, don't hesitate to take a look at this other article that 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 vaccinations) can cause inflammation and swelling of the face and body, including the extremities. In these cases, the swelling is often accompanied by itching, reddening 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.
This is a pathology that fundamentally affects puppies between 3 and 7 months, of large breeds such as the Weimaraner or the Great Danish. It is usually associated with inadequate feeding of puppies (due to overnutrition, excess protein or calcium), although it also seems to be related to quadrivalent vaccination and distemper virus infections.
Normally the metaphyses of long bones such as the ulna/radius or tibia are affected. In addition to swelling at the level of the bone metaphyses, you can see pain, fever and anorexia.
We leave you more information about Anorexia in dogs: causes, diagnosis and treatment, in this post on our site.
Bone tumors
In dogs, bone tumors can be classified into two large groups:
- Primary bone tumors: are those that have their origin in the bone itself. Osteosarcomas are the most common, although fibrosarcomas, chondromas, and chondrosarcomas, among others, can also be seen.
- Secondary or metastatic bone tumors: produced by metastases from malignant tumorspresent in other areas 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 a variable degree of lameness may be seen.
At this point, we must mention a pathology that, despite not having a tumor origin, courses in a very similar way to tumors. This is hypertrophic osteopathy, a disease in which there is a proliferation of the outermost layer of the bones (the periosteum). Generally, it appears in response to a pathology in another region of the body (such as lung tumors, granulomas or dirofilariosis), although its pathogenesis is not entirely clear The positive part is that once the primary cause is removed, the bone lesions disappear.
Inflammatory processes
Inflammatory processes in the soft tissues of the extremities can lead to focal swelling. Unlike other processes in which a broader or generalized thickening occurs, in these cases a well-defined swelling in the form of a noduleis observed.
Depending on the chronicity of the inflammatory process, we can differentiate:
- Abscesses: in cases of acute inflammation due to bacterial infections.
- Pyogranulomas: in subacute inflammations caused by foreign bodies (such as spikes).
- Granulomas: in chronic inflammatory processes caused by fungi or parasites.
Likewise, trauma from falls, blows, run over, or dog fights can also cause swelling of the extremities due to the inflammatory process that occurs as a result of trauma. In addition, when these traumas give rise to a fracture,the swelling of the soft tissues surrounding the fractured bone is even more striking.
Symptoms of swollen paws in dogs
In the first part of this article we have talked in general about the different causes that can cause swelling of the legs of dogs. However, in each process the swelling appears and evolves in a different way. In this way:
- In the case of edema or lymphedema: Usually more than one limb is affected. In these cases, the swelling begins in the distal area of the extremities (part farthest from the trunk) and progresses to the proximal (part closest to the trunk). In addition, it is characteristic that when the affected tissue is pressed firmly with the finger, a depression (known as a pit) occurs that persists for a few seconds after the finger is removed.
- In the case of bone tumors, trauma and fractures: only swelling is observed in the affected limb.
- In arthritis: the swelling is limited only to the affected joint. Similarly, in developmental diseases such as metaphyseal osteopathy, swelling is observed only at the level of the affected metaphysis.
- In the case of local inflammatory processes: such as abscesses, granulomas or pyogranulomas, a localized swelling is observed, like a nodule.
In addition, depending on the cause of the swelling, very different symptoms may be observed and associated with different organs and systems. It will be essential to take into account the set of clinical signs presented by the animal to guide the diagnosis and establish the most appropriate treatment.
How to prevent swollen paws in dogs?
Unfortunately, Many of the causes that can lead to swollen paws in dogs, such as tumors, allergies or immune-mediated processes, cannot be preventedHowever, there are other pathologies that occur with this sign, which can be avoided by taking into account a series of preventive measures:
- Compliance with the vaccination and deworming schedule: with this simple preventive measure you can avoid all the infectious and parasitic causes that can be associated to the appearance of swollen paws in dogs. Check here the Schedule of vaccinations for dogs.
- Offer an adequate diet: as we have explained, malnutrition can cause edema and, therefore, swelling of the extremities. At the opposite extreme, hypernutrition in puppies can cause developmental diseases that also cause swelling of the limbs. Therefore, it is essential to provide a balanced diet according to the needs of each animal.
- Routine veterinary check-ups: through routine check-ups it is possible to detect early some of the pathologies that we have described in this article, before even that they lead to swelling of the extremities. Carrying out early diagnosis of these pathologies will enable appropriate treatment to be established and prevent the appearance of this and other clinical signs.
What to do if my dog has swollen paws?
As we have explained throughout the article, there are multiple causes that can lead to swollen paws 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 compromise the life of the animal. For this reason, whenever you detect that your dog has swollen legs, it is important that you go to your trusted veterinarian With a correct diagnostic protocol, you will be able to determine the cause of this alteration and establish a treatment for swollen legs according to the cause.
