The occupational therapist will pinpoint the types of sensitivity and then use various implements/activities to help the child adjust. If you do a search for 'tactile defensiveness' you'll find plenty of information.
This started while she was quite young. What kind of treatment is involved?
It can be, but more likely it represents a type of sensory integration problem involving sensitivity to touch, or tactile sensitivity. An occupational therapist could determine if this is so.