BackgroundThe present clinical trial assessed the effectiveness of photodynamic therapy in association with topical acyclovir in the treatment of herpes labialis in adolescent patients. Materials and methods45 individuals with herpes labialis were divided into three groups on the basis of provision of treatment. (a) Group I: Topical acyclovir therapy (AVT) (n = 15, mean age: 17.5 years) (b) Group 2: photodynamic therapy (PDT) (n = 15, mean age:16.8 years) and (c) Group III: AVT + adjunctive PDT (n = 15, mean age: 17.0 years) respectively. HSV-1 quantification and pain scales [visual analogue scale (VAS) and McGill Pain Questionnaire (MPQ)] were calculated. Pro-inflammatory biomarkers including interleukin (IL-6) and tumor necrosis factor-alpha (TNF-α) were quantified using enzyme linked immunosorbent assay (ELISA). Shapiro-Wilk test was used to assess the normality. The Friedman test was employed to compute the comparison for changes recorded in pain scores, proinflammatory cytokines and HSV-1 quantification, whereas Mann-Whitney test was used to analyze the mean values and establish inter-group comparisons. All assessments were performed at baseline, immediate post op, 2-weeks, 4-weeks, 3-months, and 6-months. ResultsA total of 44 individuals completed the clinical trial. According to the data obtained from the clinical assessment, all the study groups reported a decrease in the parameters being observed. However, Group III (anti-viral (acyclovir) therapy + adjunctive PDT) showed a statistically significant decrease, in comparison to Group II (PDT) and Group I [AVT] respectively. The quantified HSV-1 among all groups showed significant reduction among all groups at each successive follow-up. However, Group-III (AVT + PDT) showed statistically significant reduction as compared to Groups I and II, respectively (p < 0.05). ConclusionTopical anti-viral therapy with adjunctive PDT significantly helped in reducing the pain and pro-inflammatory biomarkers in adolescent herpes labialis patients.