Bleeding under the skin is typically the result of injury; however, it could also indicate certain bleeding disorders and cancers. Immune-mediated thrombocytopenia, an autoimmune disorder in which the dog’s body attacks its own platelets, is more likely to occur in female dogs and in the German Shepherd, Greyhound, Cavalier King Charles Spaniel and Old English Sheepdog breeds. Canine thrombopathia is a congenital defect in platelet functioning and has only been found in a few breeds such as the Spitz and Basset Hound. Lymphoma is a cancer of the immune system and is more commonly found in the Boxer, Golden Retriever, Saint Bernard, Basset Hound, Airedale Terrier, Bulldog and Scottish Terrier breeds. Von Willebrand’s disease is a deficiency in the clotting protein known as von Willebrand’s factor and most commonly occurs in the Doberman Pinscher, German Shepherd, Golden Retriever, Miniature Schnauzer, Pembroke Welsh Corgi, Standard Manchester Terrier, Standard Poodle, Scottish Terrier, Basset Hound and Shetland Sheepdog breeds.

While humans can bruise after bumping themselves, this shouldn't occur in dogs due to the protection offered by their fur and thicker skin. However, significant trauma can lead to bruising.

The only symptoms of bleeding under the skin are bruising, petechial, and ecchymosis. Other than the fact that ecchymosis may appear on mucous membranes, it can be difficult to distinguish from bleeding. If your dog’s bleeding under the skin is caused by the presence of an underlying disorder, she may exhibit additional symptoms, discussed at length below in the Causes section.

The most common cause for bleeding under the skin of dogs is simply bodily injury or trauma. However, over-sensitive, excessive or chronic bleeding under the skin may be caused or exacerbated by one of the following disorders:

Diagnosis depends upon thorough reporting of the extent and onset of your dog’s symptoms and any injury or other possible causes. Description of the physical trauma your dog may have suffered will help the veterinarian to determine if the bleeding under your dog’s skin is appropriate or if it may be exacerbated by an underlying disorder. Reporting of medical history and possible ingestion of toxic substances will also be integral to diagnosis. The veterinarian will immediately start the visit by performing a thorough physical examination to search for additional instances of bruising, petechiae, ecchymoses and/or lesions.

The veterinarian will sample your dog’s blood and perform a complete blood count, measuring red and white blood cell and platelet counts, which may indicate that your dog has lymphoma (if white blood cells are abnormally low) or thrombocytopenia (if platelets are abnormally low). Additionally, a clotting test will be performed, which could reveal thrombopathia, von Willebrand’s disease, or acquired protein clotting disorder. This test will also determine if your dog needs to be treated for anemia due to blood loss. A bone marrow sample may be taken if estrogen toxicity is suspected. Bone marrow testing can also indicate if the cause of bleeding under the skin is chemotherapy; however, this is only possible if your dog is undergoing chemotherapy treatment.

A chemical blood profile will be examined and may indicate underlying liver or kidney disease. A urinalysis will be examined for elevated proteins in the urine and blood in the urine, which could point to immune-mediated thrombocytopenia or lymphoma.

For primary bleeding under the skin, no treatment is necessary, as bleeding will stop on its own and your dog’s skin will return to normal. However, for bleeding under the skin as a symptom of an underlying disorder, treatment of the underlying disorder will be necessary. Specific treatments will depend upon the specific cause. In some cases, your dog may need to be hospitalized and stabilized through IV fluids for hydration and proper electrolyte balance and possible whole blood or packed red blood cell transfusion in the case of anemia or platelet transfusion in the case of a severe platelet deficiency.

It is important to follow the veterinarian’s instructions for follow-up appointments and at-home care. Minimize your dog’s activity during recovery in order to prevent further injury.

In many cases, it's been historically proven that treatment of the underlying cause will lead to a full recovery; however, if your dog has a congenital bleeding disorder, treatment will be long term management. For dogs with congenital bleeding disorders, excessive bleeding will need to be managed for the rest of their lives. During a bleeding episode, restrict movement in order to minimize bleeding. Dogs with congenital bleeding disorders who exhibit bleeding gums as a symptom should be fed only soft food and not given hard chew toys or bones.

The veterinarian will most likely need to hospitalize your dog and provide him with intravenous fluids ($67 to $85). However, your dog may also require overnight observation ($40 to $120 per night). The veterinarian may diagnosis the bleeding under your dog’s skin as a symptom of anemia. Anemia is a condition of the blood where there is a red blood cell deficiency, resulting in thinner blood and poor health. The veterinarian may treat this by providing your dog with a whole blood transfusion ($500 per unit). Another possibility is that the bleeding is a symptom of a platelet deficiency. Platelets clump together to stop bleeding. If there aren’t enough platelets in the blood then clots cannot be formed. In this case, a platelet transfusion ($150 to $450 per unit) can help resolve the issue.

Keep in mind that these disorders tend to have an underlying cause and successful treatment of this may come with significant expense, particularly in the case of a cancer.