If you suspect that your dog is suffering from a tail swelling at the base, your first step should be to contact your veterinarian. They will likely want to rule out any underlying medical conditions and perform necessary tests. Depending on what the results of those tests are, the doctor may suggest treatment options for your pet. Here are some common causes of tail swelling at the base: Tumors Infections Inflammatory bowel disease (IBS) Food allergies Kidney problems Heart condition Other health issues like diabetes, cancer, etc. If you have other questions about treating your dog's tail swelling, please leave them in the comments below!