Laser surgery can be done to to close off blood vessels supplying the port wine stain. This kind of treatment should be used when the port wine stain is still flat, before it becomes thicker.
Bruising and discoloration can occur right after laser treatment. Repeated treatments are usually needed.
If treated early on, port wine stains improve dramatically.
Monitoring is based on appearance alone, unless the port wine stain is part of some other underlying condition.