Trichotillomania is an Impulse control disorder, which occurs when a person suffers from stress overload and anxiety. The sufferer starts pulling hair from scalp, eyelashes to cope with stress.

Trichotillomania is a form of self-harm. It may occur in people who have been going through stress, anxiety, depression, relationship issues and harassment for a long time. In people suffering from trichotillomania, an urge to pull out their hair develops when they are sad or stressed. Affected persons get temporary relief after pulling their hair out, which releases endorphins in their body. Other secondary symptoms of trichotillomania include picking one’s skin, biting nails, high anxiety levels, panic attacks and obsessive thoughts. At present, there is no particular treatment available for trichotillomania.
A person suffering from this compulsive disorder most often pulls hair from the scalp to feel the pain. According to experts, emotions like guilt, anxiety, self-loathing and low-esteem may trigger trichotillomania. Women going through sexual abuse might pull their hair out to look physically unattractive. It could be related to genetic disorder in much younger kids when they start pulling their eyelashes and hair from the scalp.
There is no specific treatment for trichotillomania at present. Habit Reversal Training (HRT) is practiced to make the person aware of the impulse to pull their hair and control this urge. This training has shown major success in treating many other self-harm disorders. Other than that, doctors prescribe several anti-depressants like Acetylcysteine and Clomipramine. The person is taught to relax and de-stress in order to avert the impulse of pulling out one’s hair.
References:
http://en.wikipedia.org/wiki/Trichotillomania
http://abcnews.go.com/Health/PainManagement/story?id=6332680&page=1
http://abcnews.go.com/2020/story?id=123719&page=1
http://jeyfiles.blogspot.in/2011/02/girl-who-eats-hair.html
http://abcnews.go.com/Health/PainManagement/story?id=6332680&page=1
Source-Medindia