Treatment and Classification of Nevus of Ota: A Seven-Year Review of a Single Institution's Experience

BACKGROUND: Nevus of Ota (NO) is a relatively common pigmentary disorder in Asians. Tanino's classification is an old but tacit consensus to delineate the disease. Various treatment options have been presented. However, a few studies have been conducted on available laser options and current treatment strategies or the classification of NO. OBJECTIVE: To investigate current laser options and their effectiveness for the treatment of NO, contributing factors to clinical outcomes, and verification of classification. METHODS: A retrospective study of NO was conducted by reviewing medical charts and photographs of sixty-seven patients. Statistical analysis was used to compare excellent and poor outcomes and determine contributing factors. RESULTS: The median age of onset was below the age of 1 (interquartile range [IQR], 0~1). Tanino's and PUMCH classification systems failed to classify patients in 24 (35.8%) and 6 (9.0%) of patients, respectively. A 1,064 nm Q-switched Nd:YAG laser without additional lasers was used most frequently in 42 patients (62.7%). The frequency of treatment was 19.0 (IQR, 10.0~23.0) in the cured group defined as subjects showing 95% improvement or above, compared to 10.0 (IQR, 6.25~13.75) in the unattained group defined as subjects showing less than 95% improvement (p=0.001). CONCLUSION: A 1,064 nm Q-switched Nd:YAG laser is a reliable treatment armamentarium, functioning as a single infallible modality as well as a combination treatment modality for NO. Repetitive laser treatments without interruption seems to be the most suitable in clearing NO. The current classification systems of NO are defective. Thus, a new classification should be developed.