Platelet-rich plasma in alopecia areata: intradermal injection versus topical application with transepidermal delivery via either fractional carbon dioxide laser or microneedling

INTRODUCTION: Alopecia areata (AA) is a common cause of non-scarring alopecia with variable response to treatment. Platelet-rich plasma (PRP) stimulates proliferation and differentiation of stem cells in the hair-follicle bulge via multiple mechanisms. Although beneficial, pain during injection in addition to unequal delivery and coverage is a major drawback of intralesional PRP in alopecia, particularly for extensive lesions and in patients with a low pain threshold. This study evaluates intradermal injection of PRP versus its topical use with enhanced transepidermal delivery through either fractional CO2 laser (FCL) or microneedling in treatment of AA. METHODS: Sixty AA patients were randomized into three equal groups to receive monthly sessions of either PRP intradermal injection, FCL followed by topical PRP, or microneedling followed by topical PRP for 3 consecutive months. Assessment was done through the Severity of Alopecia Tool (SALT) score and patient satisfaction at the end of sessions (2 weeks after the last session) and after 3 additional months of follow-up. RESULTS: Patients in all groups showed satisfactory results of PRP treatment, with statistically insignificant differences in the degree of improvement among patients of the three groups studied according to the two assessment parameters. Intralesional PRP injection was associated with significantly higher pain scores. CONCLUSIONS: PRP is potentially effective and safe for treatment of AA. FCL and microneedling could facilitate topical PRP delivery and considerably decrease pain associated with intradermal injection while preserving PRP efficacy. These methods could be helpful for extensive lesions and in children.