A vascular birthmark is a colored mark on the skin caused by blood vessels that didn’t form correctly before or shortly after birth. Some are faint pink patches that disappear within months. Others are raised, deep red growths or permanent stains that may need treatment. Nearly all vascular birthmarks fall into two categories: tumors (where blood vessel cells multiply too quickly) and malformations (where blood vessels form with an abnormal structure but don’t overgrow).
Understanding which type your child has matters because the two categories behave very differently and call for different approaches.
Vascular Tumors vs. Vascular Malformations
The distinction between these two groups drives every decision about monitoring and treatment. Vascular tumors, the most common being infantile hemangiomas, involve actual cell growth. They appear in the first weeks of life, expand rapidly, then slowly shrink on their own. Vascular malformations, by contrast, are structural errors in blood vessels that are present at birth and grow proportionally with the child. They don’t shrink spontaneously.
Doctors classify malformations further by the type of vessel involved: capillary, venous, lymphatic, or arterial. An ultrasound with Doppler imaging can distinguish between “high-flow” malformations (involving arteries, with detectable arterial pulsing and shunting) and the more common “low-flow” types (capillary, venous, and lymphatic), which helps narrow the diagnosis without invasive testing.
Salmon Patches: The Most Common and Least Concerning
The faint pink or red patches many newborns have on the forehead, eyelids, or back of the neck are called nevus simplex, commonly known as salmon patches, “angel kisses,” or “stork bites.” These flat marks are caused by dilated capillaries close to the skin’s surface. They’re extremely common, and 95% of them fade within the first two years of life without any treatment. Patches on the back of the neck sometimes persist into adulthood but are typically hidden by hair and cause no health issues.
Infantile Hemangiomas
Infantile hemangiomas are the most common vascular tumor in infants, affecting roughly 4.5% of newborns. They occur three times more often in girls than boys, and premature infants weighing under one kilogram have a much higher rate, between 22% and 30%. These birthmarks often aren’t visible at birth but appear within the first four weeks, sometimes starting as a pale spot or a small red area that grows quickly.
Growth and Fading Timeline
Hemangiomas go through a predictable life cycle. The rapid growth phase happens during the first year, with most of the expansion packed into the first four to six months. After that, growth slows considerably, and most hemangiomas have finished enlarging by the time a baby is four months old. The mark then enters a quiet period before it begins to involute, meaning it gradually shrinks from the center outward. Involution can start as early as a few months of age or as late as two to three years.
About half of all hemangiomas finish shrinking by age five, and 70% are resolved by age seven. The remainder may take an additional three to five years. After involution, some leave behind loose skin, a faint discoloration, or a slightly different texture where the growth was, especially if the hemangioma was large.
When Hemangiomas Need Treatment
Most hemangiomas are left alone because they’ll resolve on their own. Treatment becomes necessary when a hemangioma threatens vision (near or on the eyelid), blocks the airway, ulcerates and bleeds, or grows large enough to risk permanent scarring. The first-line treatment is an oral beta-blocker, which slows the growth of blood vessel cells. Treatment typically starts at a low dose, increases gradually over about two weeks, and is maintained for six months.
For small, superficial hemangiomas that don’t warrant oral medication, a topical beta-blocker applied directly to the skin is an option. Studies pooling data from multiple trials found that about 83% of small superficial hemangiomas responded to topical treatment, with response rates in individual studies ranging from 47% to 100% depending on the hemangioma’s size and location. This approach works best for flat or slightly raised marks that aren’t ulcerated and aren’t near the eyes or mouth.
PHACE Syndrome
In rare cases, a large hemangioma on the face or head signals a condition called PHACE syndrome, where the birthmark is accompanied by abnormalities in the brain, arteries, heart, or eyes. The brain involvement typically affects a small area at the back of the skull responsible for balance, coordination, and breathing, which can lead to movement difficulties or developmental delays. Narrowed arteries in the head or neck can restrict blood flow to the brain, raising the risk of seizures or stroke. The female-to-male ratio for large facial hemangiomas linked to PHACE syndrome is 9 to 1. Any infant with a large segmental hemangioma on the face is usually screened with imaging to rule this out.
Port-Wine Stains
Port-wine stains are flat, pink-to-deep-purple marks present at birth, most often on the face. Unlike salmon patches, they don’t fade. They’re a type of capillary malformation caused by a specific genetic error: a mutation in a gene called GNAQ within the cells lining the blood vessels. This mutation keeps a growth signal permanently switched on, causing the capillaries in that area to stay abnormally dilated. The mutation occurs randomly during fetal development in just the affected patch of skin, so it isn’t inherited from parents and won’t be passed to future children.
Over time, port-wine stains tend to deepen in color and can develop a thickened, cobblestone-like texture in adulthood, which is one reason many families pursue treatment early. Pulsed dye laser therapy is the standard approach. The laser targets the red pigment in blood, generating heat that collapses the dilated capillaries without damaging the surrounding skin. Port-wine stains typically fade by about 80% after eight to ten treatment sessions. Treatments are spaced several weeks apart, and younger children often respond better because the vessels are thinner and closer to the surface.
When a port-wine stain covers the forehead or upper eyelid, doctors check for Sturge-Weber syndrome, a condition where the same type of capillary malformation extends to the brain’s surface and can cause seizures, glaucoma, or developmental differences.
Venous Malformations
Venous malformations are soft, compressible, blue or purple masses under the skin caused by abnormally formed veins. They’re classified as low-flow lesions, meaning there’s no arterial pulsing when examined with Doppler ultrasound. They grow proportionally with the child and can swell with activity, straining, or when the affected area hangs below the heart. Pain is common, often caused by small blood clots forming inside the abnormal veins.
When treatment is needed, the most common approach is sclerotherapy: a substance is injected directly into the malformation to damage the lining of the abnormal vessels, triggering clotting and scarring that causes the mass to shrink. Several different agents are used depending on the size and location of the malformation. For large venous malformations, ethanol is highly effective but carries significant risks including tissue damage and nerve injury, so it’s reserved for cases where the benefit clearly outweighs those risks. In sensitive areas near the airway or eyes, gentler agents are chosen specifically to minimize swelling that could compromise breathing or vision. Most patients need multiple sclerotherapy sessions over months or years to manage symptoms.
Arteriovenous Malformations
Arteriovenous malformations (AVMs) are high-flow lesions where arteries connect directly to veins, bypassing the normal capillary network. On Doppler ultrasound, they show distinctive arterial flow patterns and shunting that set them apart from the low-flow types. AVMs can feel warm to the touch and may have a palpable pulse. They’re present at birth but often don’t become noticeable until puberty, trauma, or hormonal changes trigger expansion. Unlike hemangiomas, they never shrink on their own and can progressively enlarge, sometimes causing pain, bleeding, or skin breakdown over the affected area. Treatment typically involves a combination of procedures to block the abnormal connections and, in some cases, surgical removal.
How Vascular Birthmarks Are Diagnosed
Most vascular birthmarks can be identified by their appearance and behavior. A hemangioma that appears in the first weeks and grows rapidly looks and acts nothing like a flat, stable port-wine stain. When the type isn’t obvious from the surface, ultrasound with Doppler is the first imaging step. It’s painless, doesn’t involve radiation, and reliably separates high-flow from low-flow lesions. For deeper or more complex malformations, MRI provides detailed mapping of how far the abnormal vessels extend and which surrounding structures are involved, which is essential for planning any procedure.
The key detail that shapes the entire approach is whether the birthmark is a tumor or a malformation. Tumors have a growth phase and a natural end point. Malformations are permanent structural issues that are managed rather than waited out. Getting this distinction right early avoids unnecessary worry for marks that will resolve and ensures timely treatment for those that won’t.