Alopecia is a type of hair loss that can affect a small or large part of the body. Baldness is the loss of all or part of one's hair. Baldness and alopecia can vary in severity and pattern, but the underlying reason is abnormal hair loss. For males, hair thinning occurs in the brow, temples, and progresses to the crown. The frontal and prefrontal lobes are affected by female pattern hair loss. Heredity, hormonal changes, medical issues, or age could all be contributing factors.