Yeast infections are rarely life-threatening and can usually be remedied within a few weeks or a few months of treatment. Relapses are possible, which may require regular rounds of treatment multiple times a year.
A yeast infection could also indicate a more serious underlying condition. Dogs with yeast infections from compromised immune systems are at risk of more serious infections. Even if that never happens, a yeast infection is very uncomfortable for your pooch. The sooner you start treatment, the sooner your dog can return to their normal, happy self.