There could be several reasons why the bridge of your dog's nose is swollen. One possible cause could be an allergic reaction. Dogs can develop allergies to various substances, such as pollen, dust, or certain types of food. When a dog has an allergic reaction, their body produces histamines, which can cause inflammation and swelling in different parts of its body, including the nose. Other signs of an allergic reaction may include itching, redness, and a runny nose. Another possible cause of swollen nasal bridges in dogs is an infection. Bacterial or fungal infections can develop in the nose, causing inflammation and swelling. These infections can be caused by various factors, such as an injury to the nose or exposure to contaminated materials. In addition to nasal swelling, other symptoms of a nasal infection in dogs may include discharge from the nose, sneezing, coughing, and difficulty breathing. If you notice any of these symptoms in your dog, you must take them to a veterinarian for an accurate diagnosis and treatment plan.