Ota's nevus is a dermal melanocytic disease which causes serious cosmetic problems for affected individuals. Recently
Q-switched lasers with a pulse duration of 100 nsec or less became available for patient treatment. We evaluated the clinical efficacy of the Q-switched
alexandrite laser (755 nm, 100 nsec) in relation to the histopathological findings. Fifty-five Korean patients with
Ota's nevus were treated with a Q-switched
alexandrite laser for three sessions (7.5 J/cm2) at three month intervals. Skin biopsies were taken in all of the patients before treatment and immediately
after treatment in five patients. Clinical effectiveness and side effects were evaluated by direct observation and photographs. Pigment clearing was excellent in 27 patients (49%), good in 17 patients (31%), fair in 7 patients (13%) and poor in 4 (7%) patients. Postinflammatory
hyperpigmentation developed in 30 patients (55%) which resolved within four months. But there were no serious complications including
scarring or textural change. The therapeutic outcome was not affected by color but by depth of the
nevus.
Nevi of Ota with depth of 1 mm or less were associated with excellent or good results. Q-switched
alexandrite laser is a very effective and safe tool for treating
Ota's nevus. Depth of 1 mm or less of dermal melanocytes was a good prognostic marker.