RESUMO
BACKGROUND: Alopecia areata (AA) is a complex immune and polygenic inflammatory disease that causes hair loss on some or all areas of the body; extent, severity and progression vary widely among individuals. Alopecia areata, considered one of the most frequently occurring immune diseases, affects 0.2% of the world population at any given time. Uncertainty prevails about the most appropriate intervention for AA. The aim is to evaluate the effectiveness and safety of over 80 interventions for AA, including minoxidil - one of the most promising interventions for patchy AA in children and adults of both sexes. MATERIAL AND METHODS: An extensive search was conducted of international medical literature involving randomized clinical trials (RCTs) of AA interventions. RCTs were evaluated qualitatively and quantitatively according to the previously published protocol and for seven specific outcomes. RESULTS: The meta-analysis involving 5% minoxidil vs. placebo presented a significant difference in favor of 5% minoxidil with the moderate quality of evidence in children and adults with patchy AA (RR 8.37 [3.16-22.14], 95% CI). No severe adverse event was reported. CONCLUSIONS: Treatment of patchy AA with 5% minoxidil proved effective, and clinically and statistically safe in studies with limited sample size; quality of evidence was moderate. Further studies with sound methodological quality, more participants and outcome observations lasting longer than 6 months are needed to address remaining uncertainties.