Melasma-like hyperpigmentation induced by intense pulsed light treatment in Chinese individuals

Background: Symmetric melasma-like hyperpigmentation (MLH) has been identified in several patients following intense pulsed laser (IPL) treatment sessions. These patients exhibited no typical signs of melasma prior to IPL therapy. Objectives: To investigate the incidence of MLH in Chinese patients receiving IPL treatment and to discuss potential causative factors for this condition and potential preventive measures. Methods: 675 patients with skin types III–IV who were treated with IPL were retrospectively studied. Results: MLH was noted in 20 cases (20/675, 2.96%) within 3 months following IPL treatment session. All the patients had a pigmentary disorder prior to their IPL treatment s, the most common being photoaging or the presence of freckles. The lesions seen in 14 of the 20 cases (14/20, 70%) were multiple pigmented lesions along a wide distribution of the skin with undefined borders. Six of the cases had a strong post-treatment local reaction which also may have contributed to the MLH. In 2 cases, the original skin concern became worse following the IPL therapy and may have been a reason for the formation of MLH. In 6 cases, we noted that these individuals were not regular users of sunscreen post-therapy, despite our recommendations, which also may have contributed to the formation of their MLH. Conclusions: The adverse event and formation of IPL-induced MLH seen in Chinese individuals does have a relationship to a primary pigmentary lesion(s) and trend toward melasma prior to the IPL therapy. The IPL parameters chosen should be suitable for the skin condition being treated and should follow the recommendations of the manufacturer's default settings prior to undertaking the treatments. Post-therapy skin care and the use of appropriate sun protection are also important factors in preventing MLH.