Many men have frontal hairline recession only. Others will have thinning in the vertex (crown) of the scalp. Many times, both happen at the same time, says Dr. Amy McMichael with the Wake Forest Department of Dermatology in an email interview. The order is predicted by genetics and each person has slightly different genetics that determine when hair will begin to thin and how severe hair loss will be.
Scientists are using this knowledge to develop more effective treatments to slow or stop hair loss. Currently, only two treatments are approved by the U.S. Food Drug Administration. Minoxidil (brand name Rogaine) is applied topically, directly to the scalp to stimulate hair follicles. It has shown some success at slowing hair loss, even helping to re-grow hair. The other option is Finasteride (Propecia), which is taken orally to limit the production of the disruptive androgen DHT, which slows hair loss and promotes hair growth.
This is likely due to changes in how the body processes certain androgens, the male sex hormones. In fact, men with MPD actually inherited a genetic sensitivity to the androgen dihydrotestosterone (DHT). This sensitivity causes hair follicles to miniaturize, which shortens their life span and eventually leads them to stop growing hair. The areas most often affected by miniaturization are the crown and frontal hairline.