RESUMO
BACKGROUND: Platelet-rich plasma has shown some promise in the treatment of alopecia areata. OBJECTIVE: To evaluate the effect of platelet-rich plasma on hair regrowth and lesional T-cell cytokine expression in alopecia areata. METHODS: This was a randomized, placebo-controlled, split-head study involving 27 patients with alopecia areata (Severity of Alopecia Tool score ≥25%). Alopecia patches on either side of the scalp were randomized to receive 3 intradermal injections of platelet-rich plasma or normal saline at monthly intervals and evaluated 3 months after the last session. Lesional T-cell cytokine messenger RNA expression was compared pre- and posttreatment in the platelet-rich plasma-treated sites. RESULTS: The mean Severity of Alopecia Tool score did not change significantly compared with baseline with either platelet-rich plasma or placebo injections at any visit; however, the mean percentage reduction in the score in the platelet-rich plasma arm was more than in the placebo arm (9.05% ± 36.48% vs 4.99% ± 33.88%; P = .049) at final assessment. The mean interferon gamma (P = .001) and interleukin 17 cytokine (P = .009) messenger RNA expression decreased, whereas the mean interleukin 10 (P = .049) and FOXP3 (P = .011) messenger RNA expression increased significantly after platelet-rich plasma treatment. LIMITATIONS: Small sample size and a relatively short follow-up. CONCLUSION: Platelet-rich plasma was found to have limited efficacy in alopecia areata. However, it may play a role in restoring immune balance in the alopecic patches.