Hair loss in your case might be a result of change in hormones or
family history of baldness.
There are medical conditions that can cause it , such as high fever, diabetes, thyroid disorders lupus, and recent surgery. These will have to be ruled out by blood tests.
Dietary insufficiencies like reduced intake of protein and iron in your diet, chemicals used for dying, bleaching, straightening or hairstyling that pull your hair tight are also the reasons of hair loss on the scalp.