If you notice bruising on your dog's skin and don't recall him experiencing any recent injuries, call your vet for an examination. It's possible he's suffering from a bleeding disorder or an underlying condition of which bruising is a symptom. The latter includes diabetes, Cushing's disease, vasculitis, leukemia, bone marrow cancer or kidney or liver disease. Treatment depends on the diagnosis.
Dog Diseases That Cause Bruising
Types of Bruising
Bruising results from small amounts of hemorrhaging beneath the skin. Petechia is the classic bruise, resulting in a purplish area. If the bruise occurs on the mucous membranes, it's an ecchymosis. If your dog's bruising wasn't caused by an injury, your vet can get to the bottom of it by performing blood tests, urinalysis, a biochemistry profile, X-rays and ultrasounds.
Clotting Factor Issues
Clotting factor problems can be genetic, or triggered by ingestion of rat poison or similar chemicals. Dogs with liver disease can develop clotting issues. If you see bruising on your dog's skin, consider yourself lucky, because some dogs with clotting, or coagulation, disorders only bleed internally and you might not be able to tell anything is wrong with your pet until it's too late. Many of these clotting disorders are genetic, with certain breeds predisposed to a particular disease. For example, prothrombin deficiency occurs in cocker spaniels, causing increased likelihood of bruising. Factor VII deficiency affects beagles, boxers and bulldogs, among others, resulting in excessive bruising after surgery.
Thrombocytopenia occurs when a dog doesn't have the sufficient number of platelets in his bloodstream, with bruising one sign of the condition. Platelets help blood to clot. Thrombocytopenia can result from trauma, poisoning, chemotherapy or an immune-related disease. In addition to bruising on the skin or gums, signs of thrombocytopenia include dark, tarry stools or nasal bleeding. Your vet might prescribe corticosteroids to treat the condition, along with a blood transfusion, if necessary. In a dog with frequent episodes of immune-mediated thrombocytopenia, the vet might perform a splenectomy, or spleen removal.
Von Willebrand's Disease
Excessive bleeding, including bruising, is the major symptom of the hereditary Von Willebrand's disease. Von Willebrand's disease most often affects basset hounds, Doberman pinschers, Manchester terriers, golden retrievers, German shepherds, standard poodles, Scottish terriers, miniature schnauzers, Pembroke Welsh corgis and shetland sheepdogs, along with mixes of these breeds. There's no cure or real treatment for the disease, so owners must ensure that their dogs don't play too rough or engage in activities that easily can lead to wounds.