BACKGROUND Nevus of Ota is a congenital or acquired pigmentary disorder of the skin and mucous membranes, which are areas innervated by the first and second branches of the trigeminal nerve. Nevus of Ota is very common in Asia. Nevus of Ota was effectively treated with Q-switched alexandrite (755 nm) laser, but no detailed report existed on many Chinese cases treated with Q-switched alexandrite laser.

OBJECTIVE The objective was to gauge clinical and treatment data and material statistics for 602 cases of nevus of Ota and analyze its pathogenic mechanism and therapeutic results.

METHODS A total of 602 cases of clinical data on nevus of Ota were collected by means of clinical registration, photo verification, and telephone inquiry or correspondence.

CONCLUSIONS There are some differences in sex, age, and local regions in nevus of Ota. Nevus of Ota can combine with other diseases. The treatment of Nevus of Ota by a Q-switched alexandrite laser is safe and effective. Additional treatment will achieve good results. The results correlate to the eyelids and Tanino's classification.