Definitely talk to the pediatrician - but my daughter pulled her hair out in one spot when she was 5 years old, also just when she went to sleep - so I did some reading. Some kids just have brains that are wired to doing this - and generally it is a stress reliever - just like some people bite their nails. Maybe it is helping her unwind at the end of the day - so try to find other things. For my daughter, who admittedly was a little older so I could talk to her, I had her talk to me about what was stressing her out, and then we substituted hair pulling for hair brushing. She had a brush in her bed and brushed her hair instead when she got the urge to pull. You should also try things that will make it difficult for her to pull her hair - a cap on her head, gloves on her fingers, or bandaids on the ends of her fingers. Good luck!