Can photobiomodulation prevent herpes labialis recurrences? A systematic review.

OBJECTIVE: This systematic review evaluated the effectiveness of photobiomodulation for preventing recurrent herpes labialis. METHODS: Eligibility criteria were defined using the PICOS framework, and only randomized clinical trials were included. We searched PubMed, Embase, Scopus, the Cochrane Library, the Virtual Health Library, and gray-literature sources. Of the records identified, nine reports underwent full-text assessment, and three studies met the eligibility criteria. RESULTS: Two trials reported lower recurrence frequencies after photobiomodulation compared to control interventions, while one trial found no difference. Findings regarding recurrence severity and duration were inconsistent across studies. No adverse events were reported in the studies that provided safety data. CONCLUSION: The available evidence suggests that photobiomodulation may reduce the recurrence frequency, severity, and duration of herpes labialis. However, the certainty of the evidence was rated as low due to small sample sizes, incomplete blinding, and variations in laser parameters and comparators. These limitations restrict generalizability and preclude definitive clinical recommendations. Well-designed randomized controlled trials with standardized protocols and consistent outcome measures are needed to establish the clinical utility of photobiomodulation for recurrent herpes labialis.