Types of Birthmarks
There are two main types of birthmarks, which have different causes. Vascular (blood
vessel) birthmarks happen when blood vessels don't form correctly — either there
are too many of them or they're wider than usual. Pigmented birthmarks are caused
by an overgrowth of the cells that create pigment (color) in skin.
Vascular Birthmarks
The most common vascular birthmarks are macular stains, hemangiomas, and port-wine
stains:
Macular stains. Also called salmon patches, angel kisses, or stork
bites, these faint red marks are the most common type of vascular birthmark. They're
often on the forehead or eyelids, the back of the neck, or on the nose, upper lip,
or on the back of the head. They may be more noticeable when the baby cries. Most
often they fade on their own by the time a child is 1 to 2 years old, although some
last into adulthood.
Hemangiomas. Hemangiomas are classified as superficial when
they appear on the surface of the skin ("strawberry marks") and deep when found
deeper below the skin's surface. They can be slightly raised and bright red and sometimes
aren't visible until a few days or weeks after a baby is born. Deep hemangiomas may
be bluish because they involve blood vessels in deeper layers of the skin.
Hemangiomas grow rapidly during the first 6 months or so of life, but usually shrink
back and disappear by the time a child is 5 to 10 years old. Some, particularly larger
ones, may leave a scar as they regress that can be corrected by minor plastic surgery.
Most are on the head or neck, although they can be anywhere on the body, and can cause
problems if their location interferes with sight, feeding, breathing, or other body
functions.
Port-wine
stains. These are discolorations that look like wine was spilled on an
area of the body, most often on the face, neck, arms, or legs. Port-wine stains can
be any size, but grow only as the child grows. They tend to darken over time and can
thicken and feel like pebbles in midlife adulthood unless treated. They never go away
on their own. Ones near the eye must be assessed for possible problems involving the
eye.
Pigmented Birthmarks
The most common pigmented birthmarks are café-au-lait spots, Mongolian spots,
and moles:
Café-au-lait spots. These very common spots are the color
of coffee with milk, which explains the name. They can be anywhere on the body and
sometimes increase in number as a child gets older. One alone is not a problem. However, it's
wise to have your child checked if there are six or more spots that are larger than
a pencil eraser (for a younger child), or larger than a dime (for an older child).
Many café-au-lait spots can be a sign of neurofibromatosis
(a genetic disorder that causes abnormal cell growth of nerve tissues).
Mongolian spots. These flat, bluish-gray patches are often found
on the lower back or buttocks. They are most common on darker skin, such as on children
of Asian, American Indian, African, Hispanic, and Southern European descent. They
usually fade — often completely — by school age without treatment.
Moles (congenital nevi, hairy nevus). Mole is a general term for
brown nevi (one is called a "nevus"). Most people get moles at some point in
life. One present at birth is called a congenital nevus and will last a lifetime.
Large or giant congenital nevi are more likely to develop into skin cancer (melanoma)
later in life, although risk is low in both. Smaller congenital nevi may have
a slight increase in risk. Moles can be tan, brown, or black; flat or raised; and
may have hair growing out of them.