Progressive, diffuse scalp hair loss in a woman

A woman, aged 31 years, presented with progressive hair loss that spanned the last 5 years. She reported that she had not experienced any excessive shedding. Her medical history was unremarkable, and her social and family histories were noncontributory. The physical exam was notable for a discoid area of alopecia that measured 
8 cm x 3 cm; the alopecia was ...