The treatment of port-wine stains with the pulsed dye laser at 600 nm

The standard wavelength in the treatment of port-wine stains (PWS) with the pulsed dye laser is 585 nm. In many cases, the response to therapy is not adequate despite many treatments, depending partly on vessels out of reach of the laser. Longer wavelengths penetrate deeper into the dermis, but are absorbed less by oxyhaemoglobin, and require higher fluences. In this study, 22 patients with PWS were treated with the flashlamp-pumped pulsed dye laser using two different wavelengths, 585 and 600 nm. Four adjacent sites with PWS were treated on one occasion with 585 nm, 600 nm and equal fluence, and with 1.5 and 2 times the 585 nm fluence. The test areas were examined blindly, by four evaluators, an average of 12.5 weeks later. There was significantly less lightening with 600 nm than with 585 nm (P less than or equal to 0001) when equal fluences were used. When 1.5 and 2 times the 585 nm fluence were applied, with 600 nm the lightening was equal to that after 585 nm. However, in individual cases (11 of 22) 600 nm showed a superior lightening of at least 20% compared to 585 nm. There was slight hyperpigmentation and hypopigmentation, but no atrophy or scarring. In conclusion 585 nm remains the wavelength of choice in treatment of PWS with the pulsed dye laser. However, in cases that do not respond satisfactorily with 585 nm, it may be worth trying 600 nm with a fluence that is at least 1.5-2 times the 585 nm fluence.