Vaginitis is a condition that can be found in both puppies and older dogs. There are numerous causes such as bacterial infection, anatomical anomalies, and cancer. Your pet may let you know that there is a problem that needs to be checked by displaying signs like frequent urination and constant licking of the vaginal area. Treatment protocols vary depending on the age of the dog and the severity of the inflammation. For example, in the case of juvenile vaginitis, the condition may resolve after the first estrus heat cycle. In older, spayed dogs estrogen therapy could provide relief. Inflammation of the vagina in canines is also defined as vaginitis.
The first sign of a female dam coming "into season" is often swelling of the vulva. This swelling can occur a week before bleeding, or the day before. Other signs of heat are behavioral changes; your dam may start to hump other dams, or pups or even your leg. She may also begin to lick herself a lot. If you own more than one dam, they will usually cycle together; one dam in heat will bring other dams into heat.
It may look like a tumor or an impending prolapse and can be very unsightly and unpleasant to see. I have had a number of dog guardians rush their dog in believing that somehow the dog was having a miscarriage. In reality though what they are likely seeing is called vaginal hyperplasia.