Clinical and histological evaluation of portwine stain treatment with a microsecond-pulsed dye-laser at 577 NM.

Test treatment of portwine stains (PWS) was performed with a microsecond-pulsed dye laser at 577 nm using a 2-mm spot diameter. Although selective coagulation of the erythrocytes occurred, this did not result in bleaching of the treated area. Massive destruction of the dilated capillaries is suggested to be a prerequisite for PWS-bleaching, very probably requiring msec (instead of microseconds) laser pulses.