It's very possible that an infection or abscess has started in your girl's anal glands. This can occur spontaneously, even if the glands have recently been expressed. So I would have the area checked out by your vet. Dragging her butt on the carpet would support this, so it's possible that the vet's expression of the anal glands wasn't effective (sometimes, if they're not emptied regularly, the liquid thickens and it won't come out unless you soak the area for a while first - I'll tell you all about that in a bit). When the anal glands are filled with fluid, this causes a feeling of pressure and your dog is trying to help relieve the pressure. Scooting across the floor is one way of removing some of the fluid, but not all.
When the dog goes to the bathroom, the contracting muscles cause the glands release a small amount of fluid. They serve to mark territory and the like. Dogs with softer stools may have a difficult time eliminating the fluid naturally from the glands, because the soft stools don't apply enough pressure to help release the fluid. So, one long term option could be to try your dog on different foods. If your dog is on a medium or low quality food, consider putting her on a higher quality foods like Science Diet. Better foods are more balanced in terms of fiber and nutrients, so you're less likely to see problems like this. You can also try giving your dog veggies that are high in fiber, like carrots or broccoli. (see the "what to do" section for the specifics)
Another possibility of what could be causing your dog's problem is sort of related to the soft stool issue that I just mentioned.
Normally, the glands discharge a liquid. But when the liquid stays inside the glands for an extended period of time, it thickens. So a dog who has thicker or pasty anal gland excretions is likely having a difficult time naturally removing the fluid. Furthermore, the thicker, pasty fluid is harder to naturally excrete, so it builds up, causing the dog to scoot.
A dog with soft stools or thick excretions would be more likely to develop an infection. Soft stools don't provide sufficient pressure on the glands, causing the fluid to accumulate and eventually get infected. So in addition to ruining your carpets, it's also posing a health hazard for your dog, and you don't want that. Symptoms of a problem with the anal glands, such as an infection, include scooting, licking at the area of the rectum or sudden and unexplained changes in bathroom habits. A dog suffering from an infection may also exhibit more generalized symptoms, such as weight loss, poor appetite, lethargy and depression, and a general off-colorness.
WHAT TO DO:
* Begin by altering your dog's diet (gradually mix in the new food over a couple of weeks) to a higher quality food.
* Give your dog high-fiber vegetables. Carrots work the best. Many dogs will chew at them like a bone. If they're not so cooperative, you can mince them and mix them in with their normal dinner.
* If your dog is out of shape, get her walking regularly. Dogs who are out of shape and don't have good muscle tone have a more difficult time emptying the anal glands, since the muscles play a big role in this process.
* Soak your dog's rear end in the tub for about 15 minutes. (Put her in a sit position) Warm water with epsom salts (one cup of salts per two gallons of water) can help liquify the fluid inside the sacs, making the draining process much easier. Note that the salt can be drying to the dog's skin, so apply a bit of mineral oil after the bath. Do this twice a day for two days.
* After two days, begin applying warm compresses of water and epsom salt to your dog's rear. Do this for 15 minutes twice a day for a week. If you can't get your dog to sit in the bath, this can work as an alternative.
* Following the bathtub soaks and/or compresses, put a washcloth or paper towel over your dog's anal opening. Put the palm of your hand and rock it back and forth, applying a bit of pressure. This will help the glands empty naturally.
* You should also learn to drain the anal sacs yourself. (Some full service groomers will do this as well, so if you're squeemish, this could be an alternative to the vet.) This can be done after the bathtub soaks and/or compresses.
If you'd like to try to drain the glands yourself, here's what to do: Lift your dogs tail. Position a washcloth or paper towel over the anal opening. Position your fingers on either side of the glands and apply pressure while you move your fingers over the glands, toward the center.
There's a good diagram and write up on expressing the anal glands this website:
The following link will take you to an animation that will show you where the anal sacs are positioned (at approximately the 8:00 o'clock and 4:00 o'clock position).
For more information on the types of problems that can occur with the anal glands, visit http://www.vetinfo4dogs.com/doganal.html
I hope this helps you and your dog! There's a great deal you can do to improve anal gland problems on your own, but more serious issues such as infections and abscesses need help from the vet. If you don't see any improvement, don't hesitate to seek help for your dog, because a problem like an abcess can be messy, painful and require putting your dog under for cleaning and stitches!
I hope your dog is feeling better soon! Don't hesitate to let me know if you have any additional questions!
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