Hello,
There is no medical condition as such which causes oiliness of the hair. I would suggest you to clean your hair frequently with a mild shampoo(you can use the ones for oily hair) and don’t apply any conditioner on the hair. Also you can shampoo twice during each wash and apply shampoo on the scalp without piling the hair on top. For oily skin, wash frequently with a mild face
wash like Cetaphil and then pat it dry. Exfoliate on a regular basis and apply a mild hypoallergenic non cosmedogenic moisturizer.
I hope it helps. Take care and regards.