Port-wine stains (PWSs) are congenital lesions characterized by ectatic vessels in the superficial dermis. The cause of these lesions is unknown, but 1 theory is that they result from a diminished neural regulation of the blood flow, secondary to a reduced number of perivascular nerves,1 which, in turn, results in erythrostasis and progressive vessel ectasia. The use of pulsed dye lasers is currently the treatment of choice for PWSs. The 577-nm or 585-nm wavelength selectively targets oxyhemoglobin and the 450-microsecond pulse duration is sufficient to cause intravascular coagulation without excessive heat dissipation to the epidermis or adjacent dermal structures.
Kane KS, Smoller BR, Fitzpatrick RE, Walker NPJ, Dover JS. Pulsed Dye Laser-Resistant Port-wine Stains. Arch Dermatol. 1996;132(7):839-841. doi:10.1001/archderm.1996.03890310131028