P#34  A novel method for assessing regional scalp hair density in male pattern hair loss

Elise A. Olsen. Duke University Medical Center, Durham, USA

The etiological factors at play in male pattern hair loss can be assumed to be the same in all areas of the affected scalp although shallow bitemporal recession occurs in >90% of normal males at puberty and may be under additional control mechanisms than hair in the frontal, mid-top or vertex scalp. However, the four sections of the scalp designated by Olsen may have different rates and degree of hair loss and should be evaluated separately for degree of response to a given hair growth promoter. The author presents here a new method for assessing hair density that takes into account the density differences in the various scalp areas involved in male pattern hair loss. In this scheme, the aforementioned arbitrary scalp divisions of vertex (V), mid-top (M), frontal (F), and bitemporal (T) scalp are each assigned a density scale of 0 to 5 with zero being no loss and 5 being total or near total terminal hair loss. Furthermore, to more accurately assign hair density ratings within a given region where the hair loss may not be evenly distributed across the region, the scalp regions have been further divided into zones. This is especially important in the vertex region where the size of the vertex balding area varies widely and in the frontal area where the hairline may recede to varying degrees. In a typical clinical trial, regional scalp hair density would be assigned at baseline and at designated follow-up study visits. Use of this new methodology will allow determination of whether baseline hair density in a particular scalp region effects potential outcome and/or if each scalp region responds differently to a given hair growth promoter. It may also allow determination of overall Hamilton-Norwood hair loss pattern based on set criteria that will minimize interobserver variability in assignment. This regional scalp hair density method, versus Hamilton-Norwood pattern assignment alone, should allow for detection of small degrees of hair growth in response to hair growth promoters over a 6-12 month clinical trial.