I can hear the concern in your post about parasites. I tried researching a bit about parasites that resemble hair and it does seem that there are some out there, but not being a medical professional myself I do not feel comfortable sharing information from sources I am unfamiliar with.
If you feel comfortable sharing, could you tell us a bit more about what you think they are? You mention they look like hair, are they causing irritation on the scalp? You also mention that doctors have not been of any help, did they run any tests or take any samples?