Combined isobutylamido thiazolyl resorcinol and low‐fluence Q‐switched Nd: YAG laser for the treatment of facial hyperpigmentation: A randomized, split‐face study

Abstract Background Isobutylamido thiazolyl resorcinol (ITR) is a novel anti‐tyrosinase recently shown to be effective in the treatment of hyperpigmentation. Low‐fluence Q‐switched Nd:YAG 1064‐nm laser (LFQS) has proven to be effective for various hyperpigmentary conditions. However, there is no study on the efficacy and safety of combined ITR and LFQS treatment. Objectives To compare the efficacy and safety of combined ITR and LFQS with LFQS monotherapy for facial hyperpigmentation. Materials and Methods Patients with symmetrical facial hyperpigmentation were treated with five sessions of once weekly LFQS on the whole face. One side was randomly treated with ITR and the other side received a placebo cream for 12 weeks. Patients were followed for 8 weeks after the last laser treatment. Relative lightness index (RL*I), Facial Hyperpigmentation Severity Score on the malar area (FHSS m ), patient satisfaction, recurrence, and adverse events were recorded. Results Twenty‐four patients completed the study. Both sides demonstrated significant reductions of mean RL*I and mean FHSS m from baseline ( P < .01). At the 4th week, the ITR‐treated side showed more improvement of mean RL*I than the placebo‐treated side (62.5% vs 47.3% improvement, P < .05). The mean FHSS m on the ITR‐treated was reduced at a significantly higher percentage than the placebo‐treated side (54.4% vs 40.2% reduction, P < .05). Partial recurrence was observed on both sides. No serious side effects were noted. Conclusion Combined ITR and LFQS therapy was more superior than LFQS monotherapy in the treatment of facial hyperpigmentation. ITR may serve as adjuvant for patients with such condition.