Problem: My cat doesn't clean herself
She uses the litter box but doesn't clean herself afterward. I'm having to wash her rear every day or I find little brown poop spots all over my bed, carpeting and the rest of the house.
Some cats are more fastidious than others in the grooming area, but if a normally clean cat stops cleaning, that is a red flag.
Is she an older cat? Is this a new problem? Is she having diarrhea? Does she groom herself in other ways, or has she stopped cleaning herself completely?
Older cats may have difficulty cleaning, especially the hard to reach places, possibly due to pain and limited ability to move. Cats who've developed arthritis (at any age) or are injured may experience this as well.
Typically, if a cat stops cleaning and is not old then she's either injured or taking ill.
If the problem is only related to cleaning the butt area, then it very well could be a limited mobility issue due to injury or arthritis.
Now, it could instead be that she's having a bowel problem, such as constipation/diarrhea or impacted anal glands. Some cats will experience a "half-in/half-out" situation with that last bit of fecal matter if it's heavily wrapped in hair. I have, on many occasions, had to grab Frankie and "pull out" what wouldn't come out on its own because of all the hair. If you don't do that, you end up with a mess as you describe.
So, if it's a bowel problem then you'll have to treat for constipation, impacted anal glands, or other bowel problem.
So, new problem? Is she cleaning everywhere OK except the back end? Is she having a bowel issue perhaps?