Birthmarks are remarkably common. Around one in three babies is born with a birthmark of some kind, and many more develop one in the first weeks of life. Most are entirely benign, cause no health problems, and either fade with time or remain stable throughout life.
Parents are often given little information about birthmarks at birth, and the result is anxiety about marks that are either completely harmless or easily explained. Understanding the main types and their significance takes most of the worry away.
Healthbooq (healthbooq.com) covers newborn skin and health, including common presentations in the first days and weeks of life.
Vascular Birthmarks
These are caused by abnormal or dilated blood vessels near the skin surface. The main types seen in babies are salmon patches, port wine stains, and infantile haemangiomas.
Salmon patches (also called stork bites or angel kisses) are the most common birthmark of all, present in around half of newborns. They appear as flat pink or red patches, most often on the back of the neck (where they are called stork bites), the forehead, or the eyelids. They are simply dilated capillaries and are entirely harmless. Those on the eyelids and forehead usually fade within the first one to two years. Those on the back of the neck often persist into adulthood, though they become less visible as hair covers the area and the skin thickens.
Port wine stains (nevus flammeus) are present from birth as flat, pink to red-purple areas that deepen in colour with age. Unlike salmon patches, they do not fade. They are caused by a permanent dilation of blood vessels. Most are on the face. Port wine stains on the face around the eye may be associated with Sturge-Weber syndrome (a condition involving abnormal blood vessel formation in the brain and eye) and should be assessed by a specialist. Port wine stains can be treated with laser therapy later in childhood if desired.
Infantile haemangiomas (previously called strawberry naevus) are not usually present at birth but appear in the first weeks of life as a small red mark that then grows, often rapidly, over the first months. Most reach their maximum size by around six months and then very slowly involute (shrink and fade). By age seven, most have largely resolved. About 20 per cent leave some residual skin change. Most require no treatment. Haemangiomas in certain locations need earlier attention: those near the eye (which can obstruct vision), those on the airway or lips (which can affect feeding or breathing), very large ones, or those that ulcerate. Propranolol (a beta-blocker given orally) is effective at accelerating involution and is now standard treatment for haemangiomas that require intervention.
Pigmented Birthmarks
These result from clusters of melanocytes (pigment-producing cells) in the skin.
Congenital melanocytic naevi (moles present from birth) range from small (under 1.5cm) to giant (over 20cm). Small and medium moles carry a very low lifetime risk of melanoma. Giant congenital melanocytic naevi have a higher, though still relatively low, risk and are generally monitored by a dermatologist. Any mole that changes in colour, shape, size, or texture, or that bleeds, should be assessed.
Mongolian spots are flat, blue-grey areas most commonly seen on the lower back and buttocks of babies with darker skin tones. They are caused by melanocytes that have not migrated fully to the skin surface and appear deep blue because of the depth of the pigment. They are entirely benign and usually fade by school age. They are sometimes mistaken for bruises, and documenting them in the red book at birth is important to prevent confusion in safeguarding assessments.
Café-au-lait spots are flat, oval, light brown marks that can appear anywhere on the body. Single or a small number are common and entirely benign. Six or more café-au-lait spots larger than 5mm (or larger than 15mm after puberty) may be associated with neurofibromatosis type 1 and should be assessed by a GP.
When to Seek Advice
The great majority of birthmarks need nothing more than a note in the red book and perhaps monitoring at home. Seek advice from your GP if: a birthmark is changing (growing, darkening, developing irregular borders, bleeding); a birthmark is in a location where it might affect vision, feeding, or breathing; a haemangioma is ulcerating or very rapidly enlarging; there are six or more café-au-lait spots; or you have any concern about any mark.
Key Takeaways
Most birthmarks are benign and require no treatment, either fading on their own or remaining stable without causing any medical concern. The main types include vascular birthmarks (caused by abnormal blood vessels) and pigmented birthmarks (caused by clusters of pigment cells). A few rare birthmarks are associated with underlying conditions or have a small risk of malignant change and warrant monitoring. Any birthmark that is changing, bleeding, or causing concern should be assessed by a GP or dermatologist.
