Topical minoxidil solution (1% and 5%) in the treatment of alopecia areata.

Topical minoxidil solution can induce hair regrowth in alopecia areata. A dose-response effect was demonstrated when 48 patients treated with topical 1% minoxidil were compared with 47 patients treated with topical 5% minoxidil. A total of 66 patients were enrolled, 26 of them participating in both study groups. Patients with extensive (75% or greater) scalp hair loss showed a response rate of 38%, defined as terminal hair regrowth, with 1% minoxidil versus an 81% response rate with 5% minoxidil. The current 2% formulation is most likely to elicit cosmetically acceptable regrowth in those with patchy alopecia areata. Occlusion of the treated area appears to be necessary to achieve and maintain maximum results. Nonresponders are most likely to be found among those with the most extensive scalp hair loss. No other clinical features correlate with response to treatment. However, a finding of increased T cell blastogenesis before treatment may predict response. In patients with severe alopecia areata, hair loss generally recurs after treatment is stopped and may recur during treatment. Systemic absorption of topically applied and occluded minoxidil solutions (1% and 5%) was minimal; no clinically significant changes in blood pressure, weight, cardiovascular status, electrocardiogram, electrolytes, complete blood count, or urinalysis were seen. Mild local irritation occurred, and two of the 66 patients developed allergic contact dermatitis to minoxidil, as confirmed by patch tests.