My dog started limping

I have an 9 year old Lhasa apso with a little bit of poodle in her, just enough for the eye boogers basically. Anyways older small dog, she used to limp or not walk on one foot and then you would pet her or call her and it went away almost like she was faking lol. But yesterday when I took her out at night she came back not using her back left leg at all. She did run around the corner for a second but it was right by me and the was no other animals or anything like that, the weird thing is there is no pain for her if it is touched, rubbed, extended, and there are no sensitive areas at all yet she will not use it. This only started yesterday and she has a check up early next week but I just can't figure out what it is. It almost seems like what was happening intermittently when she was younger is has been for a day now.

The only thing I could think was that it could be arthritis or something. But if any of you have any ideas it would be great to here them, thanks in advance.

I used to have a pure-bred Australian shepherd that had hip dysplasia. He limped bad and always pulled up the rear when running with a pack. I do seem to remember, though, the vet telling me hip dysplasia is more of a trait in medium-large dogs, though. Something to research, I guess.

Are you sure it's a foot problem? Knee and hip problems are common in many dog breeds. She should get her hips checked out to rule that out.
My old neighbor's AB/Pit cross had bad hips and he put her on glucosamine, which helped her immensely. She stopped limping within a couple weeks of starting treatment. You really have to stick with it and make it a part of her diet permanently. Talk to your vet about the dosage for a tiny dog like that.

I am going to make sure to talk throughly with the vet about this. When I move her leg myself check for any stiffness or pain with motion there isn't any she doesn't tense on her left any more then her right so I am at a loss as to why she is limping, I talked to the vet and he said since it happened after running around hard outside and it came on so quick that she might have pulled something and is simply not using a hurt ligament. But he said to keep her appt. and if it gets worse or not better in a few days call to bring her in sooner.

give her a leg massage