It could be a tic disorder. There is really nothing you can do to "cure" it, but there are some things that help:
enough sleep
dietary changes (Feingold diet is great, check feingold.org)
Also sometimes scents will make it worse- try using unscented products (some people say chlorinated pools make their tics worse as well.)
Trying to learn triggers- prolonged reading or computer or tv, etc.
It is not technically diagnosed as Tourette's Syndrome until tics are present for one year and there is more than one type of tic (you can read up on tics- she may have some or have some OCD behaviors that go along with tic disorders that you don't even realize!)
If it begins to bother her, there are medications that can help as well. Abilify is a newer medication that gives wonderful results and with a very low dosage as well. It has relatively little chance of side effects too, in comparison with others like Zoloft, etc.
My daughter was diagnosed with Tourette's a year ago, so if you have any questions let me know. She started with eye blinking and finger flicking and then some skin picking around her cuticles and progressed to some OCD behaviors such as door shutting, etc.
Our path was this:
pediatrician (prescribed dry eye drops and allergy med)
opthamologist (told us it was to get attention)
allergist for testing (nothing showed)
homeopathic ped (did alternative allergy testing- showed a lot!!)
started Feingold program (decreased some behaviors and helped very little with tics)
psychologist/psychiatrist (started meds, Zoloft first then Abilify. Zoloft made her hyper, but Abilify has helped the tics and most of the OCD.)
Hope this helps!
M.