A vascular birthmark is a colored mark on the skin caused by blood vessels that didn’t form correctly before or shortly after birth. These marks range from faint pink patches that fade on their own to deep purple stains that last a lifetime. They fall into two distinct categories: vascular tumors, which are growths of blood vessel cells that can shrink over time, and vascular malformations, which are structural abnormalities in the blood vessels themselves and don’t go away without treatment.
Understanding which type your child has (or which type you have) matters because the outlook and treatment options are very different for each one.
Tumors vs. Malformations: Why the Distinction Matters
The medical world classifies all vascular birthmarks into two broad groups. Vascular tumors are made up of blood vessel cells that actively multiply. They can grow quickly, but many also shrink and disappear on their own. Vascular malformations, on the other hand, are areas where blood vessels simply formed with the wrong structure during fetal development. They don’t involve abnormal cell growth, and they don’t regress. They grow proportionally as the child grows and persist into adulthood.
This distinction trips up even some clinicians. The word “hemangioma” is frequently misapplied to malformations like venous malformations, which are a completely different condition with different behavior and treatment needs. A true hemangioma is a tumor. A port-wine stain is a malformation. Knowing which category a birthmark belongs to shapes every decision that follows.
Infantile Hemangiomas
Infantile hemangiomas are the most common benign tumors in infancy, affecting roughly 4 to 10% of babies. About a third are visible at birth, another 40% appear within the first four to six weeks, and the rest show up by six months. They often look like bright red, raised patches on the skin (sometimes called “strawberry marks”), though deeper ones can appear bluish or skin-colored with a slight swelling.
These birthmarks follow a predictable life cycle. They grow fastest between about five and a half and seven and a half weeks of age, typically reaching their maximum size around nine months. After that, they enter a plateau phase and then slowly fade. In 90% of cases, regression is complete by age four. The skin left behind is often normal, though some children are left with a faint scar, loose skin, or a slight color change where the hemangioma was.
Most hemangiomas need no treatment at all. However, those located near the eye, nose, mouth, or airway can interfere with vision, breathing, or feeding during the rapid growth phase. In these cases, a blood pressure medication called propranolol has become the standard treatment. It slows the growth of the hemangioma and speeds up shrinkage. Treatment typically starts at a low dose and is gradually increased over the first couple of weeks. Babies on propranolol are monitored for drops in heart rate or blood sugar, but the medication is generally well tolerated and has transformed how problematic hemangiomas are managed.
Port-Wine Stains
Port-wine stains are flat, pink-to-deep-purple patches present at birth. Unlike hemangiomas, they never go away on their own. They’re caused by a genetic mutation that happens randomly during fetal development, not one inherited from parents. This mutation affects a signaling protein in the cells lining tiny blood vessels, locking it into an “on” position that causes the capillaries to overgrow. The more cells carrying this mutation in a given area, the more severe the birthmark tends to be.
Port-wine stains can occur anywhere on the body but are most noticeable on the face. Over time, they tend to deepen in color and may develop a thickened, pebbly texture in adulthood. Pulsed-dye laser therapy is the primary treatment. The laser targets the excess blood vessels without damaging surrounding skin. A large study of 796 patients found that more than 50% improvement was seen in about 80% of people after five sessions, rising to nearly 88% after six or more sessions. Treatment is most effective when started early in life, while the skin is thinner and the blood vessels are smaller.
A facial port-wine stain carries about a 6% chance of being associated with Sturge-Weber syndrome, a condition where the same type of blood vessel overgrowth affects the brain and eye on the same side as the birthmark. Children with a port-wine stain in the forehead area are typically screened with brain imaging to check for this.
Salmon Patches
Salmon patches are by far the most common vascular birthmark. These flat, light pink marks appear on the forehead, eyelids, or back of the neck in many newborns. When found on the neck, they’re sometimes called “stork bites,” and on the forehead, “angel kisses.” They’re caused by small dilated capillaries near the skin’s surface.
About 40% fade during the newborn period, and most resolve by 18 months of age. Salmon patches on the back of the neck are the most likely to persist into adulthood, though they’re usually hidden by hair and cause no problems. These marks are entirely harmless and need no treatment.
Venous and Lymphatic Malformations
Venous malformations are the most common type of congenital vascular malformation. They appear as soft, compressible masses with a bluish or purple tint under the skin. Though present at birth, they’re not always obvious right away and may become noticeable later in childhood or early adulthood as they slowly enlarge. They grow along with the child and never shrink on their own.
These malformations can occur anywhere but are most commonly found in the head and neck (about 40% of cases), the extremities (40%), and the trunk (20%). They tend to swell during straining, and can enlarge noticeably during puberty or pregnancy due to hormonal changes. Pain is a common feature, often caused by small blood clots forming within the abnormal vessels. You might feel tiny hard spots (called phleboliths) within the mass.
Lymphatic malformations are similar in that they’re present from birth and don’t regress. They form from the lymphatic system rather than veins and can appear as fluid-filled cysts, ranging from small, spongy collections to large, translucent masses, most commonly in the neck, armpit, or pelvis. When located in the face or jaw, they can cause significant changes to bone growth over time and may require ongoing management.
When Location Creates Risk
The type of birthmark matters, but location can matter just as much. Any vascular anomaly near the airway, whether in the throat, tongue, or the tissue below the vocal cords, deserves close attention. A hemangioma in the subglottic area (just below the voice box) can obstruct breathing as it grows during the first weeks of life. Venous malformations of the head and neck can swell or develop clots, potentially blocking the airway. Some of these lesions have no visible sign on the skin’s surface, making them harder to detect early.
Birthmarks around the eye can affect vision development, particularly during infancy when the visual system is still maturing. Hemangiomas on the eyelid or orbit may press on the eye and cause a lasting difference in how clearly each eye sees if not addressed during the growth phase. Malformations involving the mouth or tongue can interfere with feeding and speech.
How Vascular Birthmarks Are Diagnosed
Most vascular birthmarks are diagnosed based on appearance alone. A doctor can usually tell the difference between a salmon patch, a port-wine stain, and a hemangioma by looking at the color, texture, and behavior of the mark. Hemangiomas that are growing as expected and aren’t near critical structures often need nothing more than regular observation.
When the diagnosis is uncertain, or when a malformation involves deeper tissues, imaging helps clarify what’s happening beneath the skin. Ultrasound can distinguish between high-flow lesions (like hemangiomas) and low-flow ones (like venous malformations). MRI provides detailed maps of how far a malformation extends, which is essential for planning treatment. In cases where a port-wine stain raises concern for Sturge-Weber syndrome, genetic testing can confirm the presence of the specific mutation responsible.