Did you buy health insurance from the Marketplace exchange? Or have to pay back the subsidy? If you went to an exchange for Health Insurance, and had to pay back some of the subsidy, part of the adjustment will flow to Schedule A.
If you get Social Security benefits the medicare deduction on your SSA-1099 will flow to Schedule A. Any health insurance on your W2 might go to schedule A.
Do you have self employment income? Did you enter any self employed health insurance under schedule C? If you couldn't use it all there then the difference goes to schedule A.
