it could also be yeast. but most likely it's the anal glands. i recommend going to the vet for this. groomers can do this but they can't tell you if it's impacted or infected or give meds if it's needed. well, they could tell you but you will then need to go to the vet and have it checked out by them and get meds. save yourself a trip and money and go with the vet.
I have a 15 year old chi who's anal sac ruptured just last week! Very painful for her and she's still got a bit of recoup time. I would recommend getting an anal sac expression at the vet whenever you notice frequent scooting. Especially as they get older because the fluid gets thicker and harder for them to do it on their own. I learned the hard way. My vet recommended a teaspoon of canned pumpkin in her food each day for the added fiber which is supposed to help.