Background: Oral corticosteroids may be effective in the treatment of severe alopecia areata (AA), but the side effects of prolonged therapy limit their use. The benefit of a single intravenous pulse of methylprednisolone has not been evaluated in patients with ongoing hair loss of less than 12 months’ duration. Objective: Our purpose was to determine the effectiveness of an intravenous pulse of methylprednisolone at 1, 3, 6, and 12 months in patients with active severe AA of less than 12 months’ duration. Methods: Forty-five patients were included in this open study. All had rapid and extensive hair loss for less than 1 year (first occurrence or relapse), with the bald area exceeding 30% of the scalp. There were 20 multifocal, 10 ophiasic, 9 universalis, and 6 totalis cases. Intravenous methylprednisolone, 250 mg, was administered twice a day on 3 successive days. Follow-up for at least 12 months (up to 29 months) was performed. The percentage of pretreatment bald area covered by hair regrowth at 1, 3, 6, and 12 months was measured. Results: No major side effects were observed. Patients with multifocal AA (n = 20) showed the best response rate, with 9, 12, 13, and 12 showing 100% or 50% to 100% regrowth at 1, 3, 6, and 12 months, respectively. Relapse occurred at 3 months in 1 patient, at 6 months in 2, and at 12 months in 4. A second pulse was tried in 2 patients with relapse with 100% regrowth that was stable at 12 and 28 months. In patients with ophiasic AA (n = 10), no total regrowth was observed; 6 had no response, 4 showed 20% to 70% regrowth at 1 month with relapse at 3 and 6 months. A second series of pulses was given to the 4 initial responders 3 to 13 months after the first series; the response rate to this second treatment was better than the first. In patients with universalis and totalis AA (n = 15), no total regrowth was observed initially; 8 patients had no response, and 3 showed 50% to 90% regrowth at 1 month, with subsequent improvement at 3 and 6 months. In 4 patients who did not show an initial response, a significant (90% to 100%) delayed regrowth was observed between 9 and 16 months after the pulse therapy. Conclusion: A single series of intravenous pulse of methylprednisolone appears to be well tolerated and effective in patients with rapidly progressing extensive multifocal AA, but not those with ophiasic and universalis AA. (J Am Acad Dermatol 1998;39:597-602.)