Mongolian spot birthmarks are distinctive blue, flat marks that appear on a baby's lower back or buttocks at birth or soon after. They're more common in darker-skinned people, but can happen in lighter-skinned people too.
These birthmarks are caused by a build-up of pigment cells (which give colour to skin) in the deeper part of the skin. They can be small or big. They're all harmless, and most will fade a lot within two years of birth.
Mongolian spots are also called dermal melanocytosis.
These common birthmarks are light-brown, flat spots, which can appear anywhere on the skin. Some children can have up to five of them over their bodies by puberty, which can be normal. If your child has lots of caf?-au-lait macules as a baby, it's a good idea to see your GP for further investigation.
You might hear caf?-au-lait macules called CALMs.
Port wine stains or vascular malformations
These birthmarks are large pink or red marks caused by tiny blood vessels that have expanded. They're present from birth. Both boys and girls get them.
Port wine stains can appear anywhere on the body, most commonly on one side of the face, on the back, or on the legs and arms. Their colour might get darker as children grow, and they might also thicken and become lumpy. They don't fade with time.
Some port wine stains fade after vascular laser treatment. Laser treatment can't completely remove these birthmarks, but it can usually lighten them a lot. Specialists recommend that treatment starts early in life. It's best if it's completed well before children start school, where they might be teased and feel embarrassed if they have these birthmarks.
If your child is born with a port wine stain, ask your doctor to refer you to a paediatric dermatologist who treats these conditions.
Salmon patches or stork marks
These birthmarks are pale pink, flat marks that are present at birth. You might see them over the baby's forehead (usually called angel's kiss), on the bridge of the nose, on the eyelids, or on the back of the neck (stork mark).
These birthmarks are very common, and most fade completely with time, leaving no marks by three years. Salmon patches on the back of the neck can stay into adult life.
Salmon patches or stork marks are also called naevus simplex birthmarks.
Infantile strawberry haemangiomas
Infantile haemangiomas are common. They're small red, flat marks that appear in the first weeks of life anywhere on the body. They're caused by an overgrowth of blood vessel cells.
As babies grow, the marks might start to get bigger and look raised and lumpy. After a year the marks usually start to shrink. They usually disappear by the time children are 10 years old, but they can leave loose skin in their place.
If the haemangioma is large, or over a child's eye, nose, lips or genitals, the mark should be treated to prevent complications like an ulcer, infection or scarring.
Depending on the site and size of the haemangioma, a child might need to use a beta blocker (propranolol) medication to stop growth and prevent complications. Some early or thin marks can be treated with a beta blocker gel applied directly to the skin. A paediatric dermatologist will prescribe and supervise these treatments.
Laser treatment is sometimes used to treat a haemangioma, particularly if the treatment can start before the haemangioma grows bigger. But this treatment can be painful, and your child will probably need several sessions.
Infantile haemangiomas appear in up to 10% of newborn babies. They're more common in premature babies. They're also three times more common in girls than boys.
Infantile strawberry haemangiomas are also called strawberry naevus birthmarks or capillary haemangiomas.