The Hamilton Norwood scale is used for:
Male androgenetic alopecia
Female androgenetic alopecia
Alopecia areata
Telogen effluvium
Ludwig scale is used in female pattern hair loss. The most common pattern of hair loss seen in women is diffuse reduction of hair density over the crown, so-called Christmas-tree pattern, with widening of the central paing line. Ref: Rook's textbook of dermatology, Edition-8, Page-66.18.