This prospective, non-randomized study aims to evaluate the efficacy and tolerability of treating port-wine stains (capillary malformations) using pulsed dye laser (PDL), potassium titanyl phosphate (KTP) laser, or a sequential combination of both. Each participant will receive all three treatments on different areas of the lesion. The primary outcome is improvement measured using the Investigator Global Assessment (IGA) scale. Secondary outcomes include pain (VAS), local adverse events, and patient satisfaction.

Port-wine stains (PWS), also known as capillary malformations, are congenital vascular anomalies affecting approximately 0.3-0.5% of newborns. These lesions, often located on the face and neck, tend to darken and thicken over time, potentially leading to psychosocial distress and reduced quality of life. Pulsed dye laser (PDL) therapy has long been the standard of care, utilizing selective photothermolysis to target dilated capillaries. Despite its safety and effectiveness, complete clearance is achieved in only 10-20% of cases.

Recently, long-pulsed potassium titanyl phosphate (KTP) lasers operating at 532 nm have emerged as viable options for vascular lesions, offering greater spot sizes, variable pulse durations, and integrated cryogen cooling systems that allow deeper and more consistent energy delivery. Clinical experience suggests that combining PDL and KTP treatments sequentially may enhance treatment outcomes, especially in resistant PWS, yet no controlled study has directly compared this approach to either treatment in isolation.

This prospective, single-center, non-randomized clinical trial aims to compare the efficacy, safety, and patient satisfaction of PDL (595 nm), KTP (532 nm), and sequential KTP followed by PDL in adults with PWS. Each lesion will be divided into three anatomically comparable areas, each receiving a different treatment modality. All treatments will be administered with cryogen spray cooling and without anesthesia, according to current clinical practice.

The primary endpoint is improvement at 6 weeks based on the Investigator Global Assessment (IGA) scale, evaluated by three blinded dermatologists. Secondary outcomes include pain during treatment (VAS), adverse events at 48 hours, and patient satisfaction scores. A total of 30 patients will be enrolled to ensure adequate statistical power and account for potential dropouts.

This study seeks to provide evidence supporting the optimal laser treatment strategy for PWS, potentially improving clinical outcomes and guiding future protocols.

Inclusion Criteria:

• Age ≥18
• Fitzpatrick skin types I-IV
• Presence of port-wine stain

Exclusion Criteria:

• Open wounds in treatment area
• Pregnancy
• Nearby metal implants
• Photodermatoses

This study does not plan to share individual participant data (IPD). The collected data will be coded and stored securely, accessible only to the investigators and regulatory authorities, in compliance with the General Data Protection Regulation (GDPR) and Spanish data protection law. Any future data sharing will be limited to aggregated, de-identified results published in scientific journals or presented at conferences, with no identifiable personal information disclosed.