ConditionSkin, hair & nails
Port-Wine Stain (Capillary Malformation)
A port-wine stain is a flat pink, red or purple birthmark caused by a capillary malformation, a patch of abnormally widened small blood vessels in the skin. It is present at birth in about 3 in 1,000 babies, usually on the face, and grows in proportion with the child. Unlike a hemangioma, it does not fade; it tends to darken and thicken with age. Most are harmless, but facial stains near the eye or forehead need checks for glaucoma and Sturge-Weber syndrome. Pulsed dye laser treatment can lighten them.
Also called: Capillary malformation, nevus flammeus, port wine birthmark, vascular birthmark
At a glance
- What it is
- A capillary vascular malformation present from birth.
- Cause
- Mostly a somatic (not inherited) mutation in the GNAQ gene in the affected skin.
- Course
- Persists for life; may darken, thicken and develop bumps (blebs) in adulthood.
- Associated conditions
- Sturge-Weber syndrome and glaucoma (forehead and eyelid stains), limb overgrowth syndromes.
- Treatment
- Pulsed dye laser, ideally started in infancy; cosmetic camouflage.
When to get help
Call 911 or go to the ER
- A seizure in a baby or child with a facial port-wine stain. Call 911 or your local emergency number
See a doctor within a day or two
- A baby with a port-wine stain on the forehead or upper eyelid who has not yet had an eye exam and neurological assessment
- A cloudy or enlarging eye, light sensitivity or watering in a child with a facial stain (possible glaucoma)
- Weakness on one side of the body or developmental regression
Book a routine appointment
- A port-wine stain at birth, to confirm the diagnosis and plan monitoring
- A stain that is thickening, darkening or developing bumps that bleed
- One limb larger or longer than the other with a port-wine stain
- Interest in laser treatment
What causes a port-wine stain
Port-wine stains develop before birth when capillaries in the skin form abnormally and remain widened. Most are caused by a somatic mutation in the GNAQ gene that occurs in a cell during fetal development; it is not inherited and is not caused by anything the parents did. Over time, the blood vessels gradually widen further, which is why stains often darken from pink to deep red or purple.
Port-wine stain vs other vascular birthmarks
| Birthmark | Present at birth? | Course | Notes |
|---|---|---|---|
| Port-wine stain | Yes | Persists, may darken and thicken | Flat initially; does not blanch fully |
| Salmon patch ("stork bite", "angel kiss") | Yes | Most fade within 1 to 2 years | On the nape, eyelids, forehead; very common |
| Infantile hemangioma | Usually appears in first weeks | Grows for months, then shrinks over years | Raised, bright red "strawberry" mark |
Where port-wine stains appear
Most occur on the face and neck, often on one side, following areas supplied by branches of the trigeminal nerve. They can also appear on the trunk, arms or legs.
Associated conditions
Sturge-Weber syndrome
Sturge-Weber syndrome combines a facial port-wine stain (usually involving the forehead and upper eyelid), abnormal blood vessels over the surface of the brain, and often glaucoma. It can cause seizures, often starting in the first year, weakness on one side, headaches and developmental delay. Babies with a port-wine stain on the forehead have the highest risk and need early assessment, sometimes with an MRI.
Glaucoma
Stains involving the eyelids, particularly the upper lid, raise the risk of glaucoma in the same eye, which can develop at any age. Regular eye pressure checks are recommended, starting in infancy.
Overgrowth syndromes
Port-wine stains on a limb may come with overgrowth of that limb or other vascular malformations, as in Klippel-Trenaunay syndrome or PIK3CA-related overgrowth.
Changes with age
- color deepens from pink to red or purple
- the skin thickens
- small raised bumps (blebs or nodules) may develop and bleed easily
- pyogenic granulomas can form
- in facial stains, the underlying soft tissue and bone may overgrow, for example enlargement of the lip or gums
Diagnosis
A port-wine stain is diagnosed by appearance. Additional assessment depends on location:
- forehead or eyelid stains: eye examination with pressure measurement, neurological assessment, and sometimes a contrast MRI of the brain
- limb stains: measurement of limb length and girth, imaging if overgrowth or other malformations are suspected
Treatment
Pulsed dye laser
The pulsed dye laser targets the hemoglobin in the widened vessels and is the standard treatment. Key points:
- treatment usually needs multiple sessions, often 6 to 10 or more, spaced weeks apart
- starting in infancy may give better results, when the vessels are smaller and the skin thinner
- most stains lighten significantly but rarely disappear completely
- some stains darken again over years and need maintenance treatment
- side effects include temporary bruising, swelling, and rarely blistering or skin color change
Other lasers (such as alexandrite or Nd:YAG) and light-based treatments may help thicker or resistant stains. Topical rapamycin combined with laser is being studied.
Other options
- cosmetic camouflage makeup
- surgery for overgrowth of soft tissues or bleeding blebs
- psychological support, as visible birthmarks can affect self-esteem
Frequently asked questions
What causes a port-wine stain?
It is caused by abnormally formed, widened capillaries in the skin, usually due to a GNAQ gene change that happens in a single cell during fetal development. It is not inherited and is not caused by anything during pregnancy.
Do port-wine stains go away?
No. Unlike salmon patches and hemangiomas, port-wine stains persist for life. They often darken and thicken with age. Laser treatment can lighten them considerably.
Is a port-wine stain dangerous?
Usually not. Most are a cosmetic concern only. However, stains on the forehead or upper eyelid can be associated with Sturge-Weber syndrome and glaucoma, so these babies need eye and neurological assessment.
When should laser treatment for a port-wine stain start?
Many specialists recommend starting pulsed dye laser treatment in infancy, when results may be better, though it can be done at any age. A dermatologist experienced with vascular birthmarks can advise on timing.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Dermatology: Port-wine stain
- International Society for the Study of Vascular Anomalies (ISSVA): Classification of vascular anomalies
- Vascular Birthmarks Foundation: Port-wine stains
- Sturge-Weber Foundation: What is Sturge-Weber syndrome
- MedlinePlus Genetics: Capillary malformation; Sturge-Weber syndrome