How old is the dog? Some dogs just get so excited to see people that they can't control it--especially puppies or younger dogs. My mom grew up with a poodle who they couldn't greet or even look at before they got her outside because she would just wet herself with excitement because they were home! If this is the case, try ignoring her until you can get her outside and then give her attention. My guess is that it is an excitement thing-she just loves to see you! :)
My beagle did this with EVERY person she encountered til about 8 months old. Didn't matter who it was or whether she knew them or just met them-LOL! She was just so excited to meet anyone and everyone.
We usually made greetings outside or made sure she did her potty before going inside.