hair pulling

my daughter will be 3 in april,
she has been pulling out her hair since about 8 months old.when she was 6 months old i moved in with a friend due to a divorce.my friend had a dog in the house also alot of dog hair.the dog went outside and new carpet replaced.she loved to play with the dog hair.it seems ever since we have done all that..she had started pulling her hair out to play with it while she sucks her thumb..i might add she only does this right before she sucks her thumb...i have went as far as shaving her head to stop her from pulling her hair out.ive given her different blankets and barbies to play with the doll hair..but it must not be the same..i really need some help her...PLEASE

[Kevin Kennedy, Ph.D.]

Dear Shelly,

This behavior, called trichotillomania, as it exists in your daughter, is a form of self soothing. You have tried a sensible approach by introducing other items with which to comfort herself. But, these behaviors tend to be very persistent - your daughter has 'learned' what is soothing to her. For now, keeping your daughter's hair short will help to prevent her actually pulling out the hair.

[Nikki]

I have a son that just turned 5 years old.  I always thought he was a very secure, well rounded young man until recently. He has been acting out in ways that I do not understand.  For example, if he is corrected he might hit his self or pull at his hair. I've asked him why, but I get no answer.  I stay home with both of my boys. (the other is 2) The 5 year old will start school this year, but I'm worried that something else is wrong. How do I stop this sort of behavior and is it something that should require a doctors help?