Certain mouse strains are much more prone to barbering than others which suggests genetics play a part in this condition. Parrots are a well known example where a distressed parrot separated from its owner will start to pluck its own feathers. There are 2 treatment approaches, one from psychiatrists and one from dermatologists. Psychiatrists will naturally focus on psychology and exploring why the child might have developed this habit. Treatment may involve therapy and in adults can involve drugs.
Dermatologists take a more direct approach.
Children with trichotillomania may be made to wear gloves. The gloves stop the sensation of touch and this makes it impossible for the person to identify suitable hairs for plucking. Sometimes a child's hair may be covered with Vaseline which makes it difficult to get hold of and unpleasant to the touch. In extreme cases the scalp may be bandaged so the child can't get at the bald area. The prognosis for children is generally good - with treatment they usually grow out of it.