To compare the efficacy and safety of 532nm KTP laser and 585 nm pulsed dye laser for treating port-wine stains.

Nevus flammeus is a vascular, primarily capillary malformation visible from birth on. In rare cases, it may also affect venous and/or arterial vascular systems of the skin or other organs [1]. It occurs in 0.3%-0.5% of the population [1], i.e. in about 3-4 out of 1000 newborns, and is thus the most frequent vascular malformation in children. The cause is a permanent dilatation of the capillary vessels, which is caused by a lack of sympathetic nerve fibers or a lower density of the same.

First-line therapy of port-wine stains consists of laser treatment with the long-pulsed dye laser [2] with a wavelength of 595nm. Treatment must be performed at least 10 times at intervals of about 8 weeks and leads to lightening and reduction of lesions. In recent years, problems have often arisen in care of port-wine stain patients because dye lasers often failed due to the instability of technology, resulting in treatment delays. Novel long-pulsed KTP lasers may be a sufficient alternative to pulsed dye lasers in treatment of port-wine stains.

Inclusion Criteria:

• Men and women 18 years and older
• Good general health, no relevant previous diseases
• Presence of one or more port-wine stains
• Cognitive ability and willingness to give consent (Informed Consent)

Exclusion Criteria:

• Age < 18 years
• Pregnant and breastfeeding women
• Significant open wounds or lesions in the region to be treated
• Missing consent and/or data protection declarations