Reflectance spectrophotometry in the objective assessment of dye laser-treated port-wine stains

At present, the treatment of choice for congenital capillary malformations of the port-wine stain type (PWS) is the flashlamp pulsed dye laser. Good results can be obtained in the majority of patients with this technique, but there is a group of poor responders. In the search for predictive tools to determine the therapeutic outcome, we have used a new photoelectric reflectance instrument. Sixty-six patients with PWS, mainly on the face, were treated with a pulsed dye laser during a 21-month period. Using a hand-held reflectance photometer, erythema indices were obtained for the PWS and normal skin. Based on these indices, a relative blanching effect could be calculated. The therapeutic result was judged to be excellent in 19, good in 20, fair in 14 and poor in 13 patients. There was a good correlation (r = 0.844) between the degree of blanching and the therapeutic result. In the 'excellent' category, an average blanching effect of 47% was present after the first treatment, and this increased to between 75 and 100% after successive treatments. In the 'poor' category, the blanching effect after one treatment averaged 14%, increasing to only 40% after up to six treatments. It thus seems to be possible to predict the outcome of therapy, which is of considerable help in treatment planning. Reflectance measurements, an objective estimate of blanching, correlate well with the clinical results, and are helpful in monitoring and predicting the therapeutic outcome in dye laser-treated PWS.