Is the child your dependent?
If not, is the child not your dependent only because the child had too much income to be claimed?
Thanks for the addtional information.
Yes, you can include any medical expenses for your dependent child on your Schedule A.
You can deduct any amounts out of pocket that you were not reimbursed by insurance and any health insurance premiums. See the article at http://www.irs.gov/taxtopics/tc502.html for more examples of allowable expenses.
I hope this helps.