Dripping from the mouth

Hi,  for years now my dog has instances where she drips from the mouth.  Not drool.  It's like a tap dripping a steady stream of water, usually right out of the back corner of her mouth.  It makes so the outside of her mouth is soaking wet.  She has to keep licking because of all of the apparent water that is collecting in her mouth.  I have had her on the same food for years and in the last week have changed (for other reasons) to a hypo-allergenic food so, it makes me think it hasn't been the food causing the problem.  It doesn't happen at any special time of day.  Any suggestions?

[Aleda M Cheng, D.V.M., C.V.A]

She may have a tooth problem, a problem with her salivary glands, or,  she could have an unusual seizure disorder.  Please have her evaluated for these possibilities by your veterinarian.