Intravenous corticosteroid pulse therapy (IVPT) has been preferentially conducted for rapidly progressive alopecia areata (RP-AA); however, the evaluation of long-term outcomes has been insufficient. In this study, 106 IVPT-treated RP-AA patients (36 males and 70 females) who were followed up for more than 1 year and up to 6.8 years were retrospectively analyzed. The mean observation period was 1137.8 ± 587.9 days (range 380-2490). The mean severity of alopecia tool (SALT) score before IVPT was 21.3 ± 23.4 but whole-scalp hair loss was observed in all cases after the intervention, suggesting that IVPT was performed soon after the onset. With additional interventions represented by intralesional triamcinolone acetonide injection with or without topical potent corticosteroid for those who insufficiently responded at 6 months after IVPT, 64.2%, 14.2%, and 21.7% of the patients respectively achieved good response (GR; SALT score ≤25), moderate response (MR; 25 < SALT score <75), and poor response (PR; 75 ≤ SALT score) 1 year after IVPT. On the final evaluation, the proportions of patients with GR, MR, and PR were 79 (74.5%), 7 (6.6%), and 20 (18.9%). Sixteen patients achieved and maintained full hair regrowth with IVPT alone until the end of observation. A previously reported scoring system for the short-term outcome prediction was shown to be useful for distinguishing the final-point GR responders from PR responders (P = 0.003). Of note, 21 patients were found to have some symptoms suggestive of the existence of preceding infectious diseases and tended to relapse. The revised scoring system adding the absence of preceding infectious diseases as one factor successfully predicted the occurrence of the relapse in our cohort (P = 0.002). Taken together, previously unreported real-world efficacy of IVPT to RP-AA was elucidated with the invention of a tool putatively enabling optimal long-term management.