B-RAF, Nevi and Melanoma: A Complex Relationship

In a study published in 2014, Ishino et al. evaluated over 300 Japanese males with and without androgenetic alopecia (AGA) using videomicroscopic techniques to assess hair density and diameter at the vertex scalp. They found that while hair density did not decrease with balding, the thickness of vertex hair significantly decreased. This suggests that hair loss in male AGA is primarily due to the miniaturization of hair follicles, which leads to the transformation of terminal hairs into vellus hairs, rather than increased hair shedding. The study also noted that the duration of the anagen phase of hair growth shortens dramatically during the development of baldness, which promotes hair shedding but does not substantially decrease hair density. Current medications for male AGA, such as topical minoxidil and oral finasteride and dutasteride, can improve hair regrowth and increase hair thickness but are unlikely to increase total hair number if hair density remains constant. The study concludes that the change in hair diameter is a reliable indicator of progression and therapeutic effects in male AGA.