The Bottom Line

A port-wine stain (also called nevus flammeus) is a permanent birthmark made up of abnormal blood vessels in the skin. It affects about 3 in 1,000 babies and does not go away on its own — in fact, it tends to darken and thicken over time if untreated. Most port-wine stains are isolated and cause no health problems beyond their appearance. However, when the stain is on the face — especially near the eye or forehead — it can sometimes be associated with conditions like Sturge-Weber syndrome, which requires monitoring. Early evaluation by a dermatologist is always a good step.

What Is a Port-Wine Stain?

A port-wine stain is a type of vascular malformation — a group of abnormally formed blood vessels that are present from birth. The name comes from the deep red-purple color of port wine. Unlike some other birthmarks (like salmon patches or strawberry hemangiomas) that fade on their own, port-wine stains are permanent. They are present in approximately 0.3% of babies born in the United States, with somewhat higher rates in babies with darker skin tones.

Port-wine stains form because the small blood vessels (capillaries and venules) in the deeper layers of the skin don't develop normally. Instead of working as they should, they stay permanently dilated and full of blood, giving the skin its characteristic reddish-purple color.

What Does a Port-Wine Stain Look Like?

Port-wine stains change in appearance over a child's lifetime:

  • In babies: The birthmark typically looks like a flat, pink or light red patch. It may be easy to miss at first. When you press on it, it partially blanches (turns lighter) — a sign that blood is being temporarily pushed out of the vessels.
  • During childhood: The stain gradually darkens, shifting from pink to red to a deeper red color.
  • In adolescence and adulthood: Without treatment, port-wine stains continue to darken and eventually take on a purple hue. The skin surface often becomes raised and nodular — bumpy like cobblestone — due to the growing and dilating vessels underneath.

The stain can appear anywhere on the body — face, scalp, neck, trunk, or limbs. On the face, it often follows the path of the trigeminal nerve (a nerve with three branches covering the forehead, cheek, and jaw areas). Most port-wine stains are one-sided, though both sides can be involved.

Is a Port-Wine Stain the Same as a "Stork Bite" or "Angel Kiss"?

No — and this distinction matters. "Stork bites" (on the back of the neck) and "angel kisses" (on the forehead or eyelids) are called salmon patches, and they are very common in newborns. Salmon patches:

  • Are lighter pink and usually fade within the first 1–2 years of life
  • Blanch completely with pressure
  • Are centered on the midline of the face (between the eyes, on the forehead)

Port-wine stains, by contrast, are deeper in color, do not fade, are usually off to one side of the face or body, and do not go away without treatment. If you're unsure which type of birthmark your child has, a dermatologist can tell you quickly.

Could a Port-Wine Stain Be a Sign of Another Condition?

Most port-wine stains are isolated — meaning they're just a skin finding with no other health implications. But in certain locations and patterns, they can be associated with other conditions:

  • Sturge-Weber syndrome: Occurs in about 8% of children with a port-wine stain affecting the forehead or upper face (V1 distribution of the trigeminal nerve). Sturge-Weber involves abnormal blood vessels in the brain, which can cause seizures, stroke-like episodes, learning difficulties, and glaucoma. Brain MRI and eye pressure checks are recommended for children with port-wine stains near the eye or upper forehead.
  • Klippel-Trenaunay syndrome: A combination of port-wine stain on a limb, limb overgrowth, and deep vein abnormalities. This is much less common.
  • Glaucoma: Even without full Sturge-Weber syndrome, port-wine stains near the eye can increase the risk of elevated eye pressure. Regular ophthalmology check-ups are important.

A port-wine stain on the arm, leg, or trunk — away from the face — is very unlikely to be associated with any internal condition and generally only needs monitoring for cosmetic reasons.

How Is a Port-Wine Stain Diagnosed?

Diagnosis is usually clinical — a doctor looks at the birthmark and can identify it by its appearance and behavior. No biopsy is typically needed. For port-wine stains near the eye or forehead, additional testing is recommended:

  • MRI of the brain and orbits: To look for the abnormal brain vessels associated with Sturge-Weber syndrome
  • Eye pressure measurement (tonometry): To screen for glaucoma
  • Full ophthalmology exam: To assess the retina and optic nerve

When to See a Dermatologist

  • Your newborn or infant has a port-wine stain — early consultation helps plan appropriate care
  • The stain involves the forehead, eyelid, or area around the eye — evaluation for Sturge-Weber is important
  • The birthmark is darkening, thickening, or developing bumpy texture — treatment discussion is warranted
  • You want to understand treatment options before the stain progresses
  • Your child has a known port-wine stain and develops new symptoms like headaches, vision changes, or seizures

Frequently Asked Questions

Will my child's port-wine stain go away on its own?

No. Port-wine stains are permanent vascular malformations. Without treatment, they do not fade — they darken and become more raised over time. This is one reason why early evaluation and, if desired, early treatment gives the best cosmetic results. For information on laser treatment, see our companion article on port-wine stain treatment options.

Does every child with a facial port-wine stain have Sturge-Weber syndrome?

No — only about 8% of children with facial port-wine stains have Sturge-Weber syndrome. The risk is higher when the stain involves the upper eyelid or forehead, or when both sides of the face are affected. A child whose port-wine stain is only on the cheek or lower face has a much lower risk. Your child's doctor will help determine whether brain imaging or eye exams are needed.

My baby's pink birthmark was dismissed as normal — should I get a second opinion?

Yes, if you're uncertain. While salmon patches (which are normal and temporary) are very common in newborns, a port-wine stain can look similar in the early weeks. If the pink area doesn't fade in the first year, is larger than a typical salmon patch, or is on the side of the face rather than the midline, it's worth having a dermatologist take a look to clarify the diagnosis.

Can port-wine stains cause pain?

Most are painless. However, in adulthood, very nodular or thickened stains can occasionally be tender. Port-wine stains near or in the eye (in the context of Sturge-Weber) may cause headaches or pain related to elevated eye pressure (glaucoma). Any new discomfort associated with a birthmark should be evaluated.

  1. Shirley MD, et al. Sturge-Weber syndrome and port-wine stains caused by somatic mutation in GNAQ. N Engl J Med. 2013;368(21):1971–1979.
  2. Waelchli R, et al. New vascular classification of port-wine stains: improving prediction of Sturge-Weber risk. Br J Dermatol. 2014;171(4):861–867.
  3. Happle R. Capillary malformations: a classification using specific names for specific lesions. Dermatology. 2005;211(3):231–239.
  4. Garzon MC, et al. Vascular malformations — Part I. J Am Acad Dermatol. 2007;56(3):353–370.

Trusted Resources

Always consult a board-certified dermatologist for personalized advice about your child's port-wine stain and any associated conditions.