Does necessity permit hair extensions for one who suffers from trichotillomania and is unable to stop?

Attaching hair to other hair is forbidden even in cases of excuse. However, attaching it to something other than hair—such as silk, which does not resemble hair—is considered permissible by some scholars. Wigs may be worn, as the ruling on them is less strict than on hair extensions, and it is permissible to wear them to protect natural hair from being pulled out.