31.    The new classification of androgenetic alopecia. 
Won-Soo Lee1, Byung In Ro2, Seung Phil Hong1, The Korean Hair Research Society Group3,  1.Department of Dermatology and Institute of Hair and Cosmetic Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea. 2.Department of Dermatology, College of Medicine, Chung-Ang University, Seoul, Korea. 3.Thirteen Dermatologic Centers, Korea.

Androgenetic alopecia is considered to be most prevalent type of hair loss occurring after the age of puberty in human. The disorder can be classified by several patterns of hair loss. Now, Hamilton-Norwood classification system in men and Ludwig grade system in women are commonly used to describe the pattern. But it has been thought that these existing classifications have some limitations. The classification methods are too detailed and complicated and less stepwise, so that it is difficult to be used actually. Since the most subjects were Caucasians in their publications, they cannot suit Korean men with androgenetic alopecia, who characteristically tend to show more ¡®female pattern¡¯ of hair thinning than Caucasians. So the existing methods cannot classify all types in all races. In addition, the clinicians must use different way by gender to classify the pattern.
Therefore, we designed to develop the new classification system which is easily available and comprehensive, regardless of race and sex, and actually to apply the new system to classify the types of androgenetic alopecia. Between November 2004 and June 2005 in thirteen dermatologic centers in Korea, total of 2213 Koreans with androgenetic alopecia (1768 men and 445 women) were analyzed the types according to sex, age, basic and special type(reflect alopecia pattern), based on the new classification system. The basic type, represent the shape and degree of anterior hair line, were divided into 4 types (Linear, M-/C-/U-shape). The special type, represent the female pattern (F) and the density of hair on vertex (V). Then, we can decide on the final type of a subject after putting together the both types. Accoding to this classification principles, type MF in men and type LF in women are the most common.