Clinical features of Ota's naevus in Koreans and its treatment with Q-switched alexandrite laser.

Ota's naevus is a fairly common pigmentary disorder in Asians. Recently, encouraging results in the treatment of Ota's naevus have been obtained, but most of these concerned the white skins of Caucasian patients. Our purpose was to examine the clinical features of Ota's naevus in Koreans and to assess the clinical outcomes and histological changes induced by a Q-switched alexandrite laser at 755 nm. Eighty-seven Koreans with Ota's naevus were studied; the peak age of onset was during the first decade and adolescence. The infraorbital area was the most frequent site and black or dark brown colours predominated. Improvements were achieved in 52 patients (77%). Better results were obtained in unilateral lesions and patients who received a greater number of treatments. Mild hyperpigmentation after treatment was noticed in 14 patients and mild hypopigmentation in eight patients. However, all of these were reversed in time. Hypertrophic scarring or secondary infection did not occur. The histology of laser-irradiated lesions showed selective thermal damage of melanocytes in the upper dermis and the elimination of upper dermal pigmentation. Our clinical data demonstrate the usefulness of the Q-switched alexandrite laser for the treatment of Ota's naevus in brown skin.