For those of you who wonder what exactly a port wine stain is (and either haven’t Googled it or are overwhelmed by the search results), it’s basically a wild proliferation of blood vessels – they never got the signal from their nerve to stop growing. 

Normally (and this is totally “Port Wine Stain 101” in layman’s terms, so double-check all this and any questions with a legit M.D.), the nerve sends a signal to its associated blood vessels to stop growing while the human is developing in utero.   Now, look at a human face from the side, and imagine three branches of the facial nerve running from the ear to the center of the face: one high (up along the forehead), one middle (straight to the nose), one low (along the jaw).  Each of these branches has blood vessels associated with it.  In Fetus Addy’s case, the middle branch of the facial nerve was the delinquent one:  somewhere along the way in utero, that nerve never gave the “okay, stop growing now” signal to its associated blood vessels, and they just kept growing.. .and growing… and growing, until they were a huge tangle (TONS of them) and huge themselves (with diameters MUCH bigger than a normal blood vessel). And, voila, a port wine stain.

These are not hemangiomas; these are not strawberries; they WILL NOT FADE with time.  In fact, as long as the body is growing… the blood vessels will keep growing, too.  So, in Newborn Addy’s case, we could expect that red port wine stain to turn purple.  And, eventually, thick and nodular as the blood vessels grew and tangled and grew some more.  Hence, our choice to zap it – and to start zapping it as soon as possible (before those blood vessels grew thicker and hardier).  For Addy, that was at 5 weeks old.

So this, hopefully, answers the basic “what is it?” question.  Soon, I’ll go into more detail about variations (because not all port wine stains are the same), recent research discoveries, and treatment (yay for pulse-dye lasers!).