RESUMEN
Port-wine stains (PWSs), or port-wine birthmarks, are congenital vascular malformations that manifest as erythematous to pink patches at birth. At present, lasers are the preferred method for treating PWSs, with pulsed dye laser (PDL) being regarded as the gold standard because of its superior efficacy compared to alternative procedures. Despite the progress made in laser therapy, a subset of patients continue to experience PWSs that cannot be resolved effectively even with PDL. A new long-pulse potassium-titanyl-phosphate (KTP) laser with a trail of sub-pulses (Derma V, Lutronic, Seoul, South Korea) is a promising treatment for PWSs resistant to PDL therapies. This is a case of a female patient with PDL-resistance PWSs that was treated successfully with a long-pulse KTP laser. Long-pulse KTP appears to be not just more effective in treating PDL-resistant PWSs but also less costly as less number of sessions are needed, with no significant side effects reported such as purpura.