Analysis of Clinical Features and Treatment Outcomes Using 1,064-nm Nd-YAG Laser with Topical Hydroquinone in Patients with Riehl's Melanosis: A Retrospective Study in 10 Patients.

Background: Hyperpigmentation on the face and neck can be a devastating psychological burden in patients with Riehl's melanosis. However, successful treatment of the disease is challenging for clinicians.

Objective: To evaluate the effectiveness and safety of low-fluence neodymium-doped yttrium aluminum garnet (Nd:YAG) laser in the treatment of Riehl's melanosis and to identify prognostic factors determining the response to laser treatment.

Methods: We enrolled 10 Korean patients with Riehl's melanosis. The patients received 10~28 treatment sessions at 3-week intervals with low-fluence Nd:YAG laser.

Results: Among all the patients, seven reached near total improvement, and two and one patient reached marked improvement and minimal improvement, respectively, after low-fluence Nd:YAG laser treatment. The mean number of needed laser treatment sessions to reach marked improvement and near total improvement was 12.1±4.0 (ranged from 6 to 17) and 14.6±4.4 (ranged from 9 to 20), respectively. A further analysis revealed the proportion of patients who reached near total improvement was higher, and the mean number of necessary laser treatment sessions to reach minimal improvement was less in patients with dark brown pigmentation compared to those with light brown pigmentation. Among all patients, three complained of guttate hypopigmentation. However, the hypopigmented lesions spontaneously improved after the interruption of the treatment.

Conclusion: We found that low-fluence Nd:YAG laser is an effective and safe treatment modality for Riehl's melanosis.