Causes of Birthmarks
Port-Wine Stains
The direct cause of Port-Wine Stains (PWS) is still not fully understood. However it is believed that the developement of PWS is a deficiency/absence of neurons that regulate blood flow through the ectatic post-capillary venules. This causes the blood vessels to be unable to constrict normally, this makes them permanently dilated. Since these blood vessels are dilated, the blood is visible through the skin, and shows up as a large red patch.
Hemangioma
A hemangioma consists of an abnormally dense group of extra blood vessels. It's not clear what causes the blood vessels to group together, however it is believed there may be a hereditary component involved.
Salmon Patches
Very similar to Port-Wine Stains, Salmon Patches are caused by expansions (dilations) in tiny capillaries. However, unlike PWS, these capillaries are only temporarily dilated and fix themselves over time.
Very similar to Port-Wine Stains, Salmon Patches are caused by expansions (dilations) in tiny capillaries. However, unlike PWS, these capillaries are only temporarily dilated and fix themselves over time.
Café-au-lait spots
Unknown as to why, Cafe-au-lait spots are caused by an increase in melanin content with the presence of a giant melanocyte. This causes an abnormal production of melanin in this one spot, causing this area to be tanner than the rest of the skin.