Fig. 1. Treatment responses according to the extent of alopecia at baseline. AA: alopecia areata, AT: alopecia totalis, AU: alopecia universalis. Extent of alopecia at baseline: mild AA: S1 (<25% scalp hair loss), S2 (25%~49%). Severe AA: S3 (50%~74%), S4 (75%~99%), AT, AU.