What causes PWS to darken and pebble with time?
Darkening and pebbling does not necessarily happen in all cases, but is certainly common. The current thinking is that the blood vessels in the port wine stain continue to grow with age (hypertrophy). This causes the skin volume in the area to increase and more blood to show through which makes it look darker. Pebbling appears to be caused by small blood vessels pushing their way up to the skin. Often times small bumps will develop that can spontaneously bleed. Typically, this doesn’t begin happening until a person is in his or her 30s, 40s, or 50s. Laser treatments are generally very effective at reducing these problems.
