A semiquantitative grading scale for frontal and vertex of androgenetic alopecia

Background Depending on the severity and region of baldness, numerous researchers proposed different classifications of alopecia. However, these previous classifications have some limitations. The study aimed to establish a semiquantitative grading scale for frontal and vertex androgenetic alopecia (AGA) in both males and females. Methods Standardized pictures from 1,602 AGA cases were obtained. Three sets of reference photographs with different alopecia extents from scale 0 to 5 were developed with detailed description. The photographs covered the vertex, frontal of men, and vertex + frontal (V+F) area of the scalp of women. Hair density and the ratio of vellus and terminal hairs in the alopecia area were quantitatively measured by DermDOC® dermoscopy. Hair coverage rate of alopecia area was calculated by Photoshop software. Multirater consensus method was used to test the reliability and validity of the alopecia scale. Results Fleiss-Kappa coefficients of the three sets of reference photographs for interobserver analysis reached 0.81-0.89. The overall Kendall's coefficients for intraobserver assessment totaled 0.934-0.963. Conclusion This new grading scale is a more sensitive and objective quantitative grading scale for alopecia and treatment response compared with the existing classification.