Birthmarks are common: roughly one in three babies is born with one, and many more appear in the first weeks of life. The vast majority are completely harmless. They either fade on their own or stay put without ever causing trouble.
The problem is that parents often leave the hospital with a mark on their baby's skin and very little explanation of what it is. So a stork bite on the neck or a flat purple patch on the eyelid becomes a worry that doesn't need to be one. Knowing the main types and what they tend to do takes most of that worry away.
Healthbooq (healthbooq.com) covers newborn skin and the small everyday questions of the first weeks.
Vascular Birthmarks
These come from blood vessels that are dilated or formed slightly differently near the skin surface. Three types account for almost everything you'll see in babies: salmon patches, port wine stains, and infantile haemangiomas.
Salmon patches (also known as stork bites at the back of the neck and angel kisses on the forehead and eyelids) are the most common birthmark of all, present in around half of newborns. They look like flat, slightly blotchy pink or red patches and are simply small pools of dilated capillaries. They are entirely harmless. Those on the eyelids and forehead almost always fade within the first one to two years. The ones on the back of the neck often stick around into adulthood, but hair and thicker skin usually hide them.
Port wine stains (nevus flammeus) are present from birth as flat, pink to deep red-purple areas, and unlike salmon patches they don't fade — they tend to deepen in colour over time. They're caused by permanently dilated blood vessels and most often appear on the face. A port wine stain involving the upper eyelid or forehead in the distribution of the trigeminal nerve can occasionally be associated with Sturge-Weber syndrome, which involves abnormal blood vessels in the brain and eye, so these need a specialist look. Pulsed-dye laser treatment can lighten port wine stains significantly, and earlier treatment (often started in infancy or early childhood) tends to give better results than waiting.
Infantile haemangiomas (the old "strawberry naevus") usually aren't there at birth. They appear in the first few weeks as a small red mark that then grows, sometimes startlingly fast, over the first months. Most reach their full size by around six months and then begin a long, slow shrink. By age seven, most have largely resolved, though about one in five leaves some residual skin change — a faint scar, a patch of looser skin, or fine telangiectasia. Most need no treatment at all. The exceptions matter: haemangiomas near the eye (which can obstruct vision and cause amblyopia), on the lip or airway (which can affect feeding or breathing), very large ones, or ones that ulcerate need earlier attention. Oral propranolol, a beta-blocker, accelerates involution and is the standard treatment when intervention is needed.
Pigmented Birthmarks
These come from clusters of melanocytes — the cells that make pigment.
Congenital melanocytic naevi are moles present from birth. They're classified by size: small (under 1.5cm), medium, large (over 20cm projected adult size), and giant. Small and medium ones carry only a very small lifetime risk of melanoma. Large and giant ones have a higher risk and are usually monitored by a dermatologist. The rule for any mole at any age is the same: anything that changes shape, colour, size, or texture, or that bleeds, gets checked.
Mongolian spots (now often called dermal melanocytosis) are flat blue-grey patches, most often on the lower back and buttocks, seen most commonly in babies of African, Asian, Hispanic, or Mediterranean heritage. The blue-grey colour comes from melanocytes sitting deeper in the skin than usual. They are completely benign and most fade by school age. They're sometimes mistaken for bruises, which is why noting them in the red book at birth matters — it prevents confusion later if anyone is asked to assess the child for safeguarding reasons.
Café-au-lait spots are flat, oval, light brown patches, the colour of milky coffee. One or two are very common and entirely benign. The number is what matters: six or more spots larger than 5mm in a child (or larger than 15mm after puberty) is one of the diagnostic criteria for neurofibromatosis type 1 and warrants a GP review.
When to Seek Advice
Most birthmarks need nothing more than a note in the red book and a passing eye over the months. Book a GP appointment if a birthmark is changing — growing faster than expected, darkening, developing irregular borders, or bleeding; if it sits where it might affect vision, feeding, or breathing; if a haemangioma is ulcerating or enlarging very quickly; if there are six or more café-au-lait spots; or if you're simply not sure and want it looked at. That last one counts.
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.
