Vascular Birthmarks in Babies: What Are They and When to See a Doctor

Vascular birthmarks are marks on the skin caused by abnormal development of blood vessels in or just beneath the skin.

They fall into two broad categories:

• Vascular tumours and
• Vascular malformations

Vascular tumours, the most common of which is the infantile haemangioma, involve an abnormal proliferation of blood vessel cells and grow faster than the child grows.

Vascular malformations, on the other hand, are structural abnormalities of blood vessels (capillary, venous, lymphatic, or arterial) that are present from birth and do not resolve on their own. They tend to grow at the same rate as the child’s natural growth.

Understanding which type you or your child has matters, because the natural history, risks, and treatment approach differ between them.

Myth #1: "All birthmarks are the same.

Fact: "Not all birthmarks are alike, and the distinction matters clinically. Vascular birthmarks, the focus of this article, involve blood vessels and include infantile haemangiomas, port-wine stains, venous malformations, lymphatic malformations, and arteriovenous malformations (AVMs).

These are different from pigmented birthmarks such as congenital melanocytic naevi or café-au-lait spots, which involve pigment-producing cells. Vascular birthmarks themselves also differ from one another.

Infantile haemangioma

An infantile haemangioma (shown above) typically appears in the first few weeks of life, grows rapidly, and then gradually involutes (shrinks) over several years.

Capillary Malformation

A vascular malformation, by contrast, such as a capillary malformation, is present from birth, does not spontaneously resolve, and may grow slowly over time or enlarge during puberty, pregnancy, or after trauma.

Myth #2: “If it’s not red, it must not be a vascular birthmark.”

Fact: Not all vascular birthmarks are red. Deeper vascular tumours and vascular malformations of veins and lymphatic vessels may not produce any surface redness at all.

Venous malformation over the right ring finger.

A deep infantile haemangioma, for instance, can present as a bluish or skin-coloured swelling rather than the bright red surface lesion most parents expect, and a venous malformation (shown above) often appears as a soft, compressible, bluish-purple swelling that is sometimes mistaken for a bruise.

Colour and depth depend on how close the abnormal vessels lie to the skin surface.

Superficial lesions tend to look red, while deeper ones appear blue, purple, or simply as a soft-tissue swelling with normal-coloured overlying skin.

This is why a lesion without any redness should not be assumed to be harmless or unrelated to the vascular system; it still warrants the same specialist evaluation as a more obviously red birthmark.

Myth #3: "A birthmark that's flat and red at birth must be a haemangioma."

Fact: This is a common source of diagnostic confusion. Infantile haemangiomas are typically not fully apparent at birth. Many appear days to weeks later and then proliferate.

Naevus simplex

A flat, well-demarcated red patch present at birth is more likely a port-wine stain (capillary malformation) or naevus simplex ("angel's kiss" or "stork bite", shown above), a distinct and usually transient lesion involving the forehead, eyelids, or nape of the neck.

Naevus simplex typically fades within the first year, while port-wine stains persist for life and warrant monitoring for syndromic associations.

Myth #4: "My child’s birthmark was caused by something I did during pregnancy."

Fact: This is not true. Vascular birthmarks are not caused by anything a mother ate, felt, experienced, or did during pregnancy.

They arise from random, localised errors in blood vessel development during foetal growth – a biological process that is not influenced by maternal behaviour and that is not usually inherited. 

There is no scientific evidence linking vascular birthmarks to stress, diet, physical trauma, or any other maternal factor.

Myth #5: "Vascular birthmarks are always inherited and will be passed on to my children."

Fact: The majority of vascular birthmarks, including infantile haemangiomas and most vascular malformations, arise from sporadic somatic mutations – random errors in blood vessel development that occur in the womb and are not inherited from parents.

The risk of a sibling having the same condition is therefore very low. That said, there are exceptions. Some vascular conditions do follow a hereditary pattern.

Capillary malformation-arteriovenous malformation (CM-AVM) syndrome for example, is an autosomal dominant condition in which abnormal blood vessels (AVMs) can occur in the skin, brain and spine.

If a parent has CM-AVM syndrome, each child has a 50% chance of inheriting it. Similarly, some familial forms of venous malformation and glomuvenous malformation are known to be inherited.

Myth #6: "Vascular birthmarks are cancerous or will turn into cancer."

Fact: The vast majority of vascular birthmarks carry no risk of becoming cancerous. Infantile haemangiomas, port-wine stains, venous malformations, and lymphatic malformations are benign conditions. 

However, "benign" does not always mean "without consequence." Some vascular anomalies can cause significant complications, including bleeding, pain, functional impairment (such as affecting vision, breathing, or limb function), and disfigurement.

Certain vascular birthmarks are also associated with underlying syndromes that require monitoring, such as Sturge-Weber syndrome (associated with port-wine stains on the face) or Klippel-Trenaunay syndrome (associated with capillary-lymphatic-venous malformations of the limbs).

Myth #7: "Laser treatment is the only option for vascular birthmarks."

Fact: Treatment for vascular birthmarks is highly individualised and depends on the type, size, location, and associated complications.

The options available today are far broader than laser alone, and often the best outcomes come from a combination of approaches managed by a multidisciplinary team. 

For infantile haemangiomas, oral propranolol is now the first-line treatment for those requiring intervention, with excellent results. Laser therapy (particularly pulsed dye laser) may be used for residual skin changes after involution. 

For vascular malformations, treatment options include sclerotherapy (injecting a solution to shrink abnormal vessels), embolisation (blocking abnormal blood flow), surgical excision, laser therapy, and in some cases, targeted medical therapies such as sirolimus, which has shown promise for complex or extensive malformations.

Many patients benefit from a combination of these approaches over time.

Myth #8: "My child's haemangioma will go away on its own, so there's no need to see a doctor."

Fact: It is correct that most infantile haemangiomas do spontaneously resolve over time. In 90% of children with infantile haemangiomas, regression is complete by 4 years of age.

For small, uncomplicated haemangiomas in low-risk locations, watchful waiting is entirely appropriate.

However, some haemangiomas require early intervention. These include haemangiomas near the eye (which can impair vision development), around the airway (which can obstruct breathing), on the face (which may leave permanent scarring if left untreated), or those that ulcerate and become painful.

Early treatment in these cases, typically with oral propranolol, a beta-blocker medication, can significantly improve outcomes.

Myth #9: "If it's not growing, it doesn't need imaging or monitoring." 

Fact: Vascular malformations can remain quiescent for years and then expand suddenly with puberty, pregnancy, trauma, or infection. 

Many families assume a stable birthmark can be safely ignored indefinitely, but periodic specialist follow-up allows subtle changes in size, colour, or symptoms to be caught early, before complications such as pain, bleeding, or functional impairment develop.

For malformations in or near critical structures, such as the airway, orbit, or major joints, imaging with ultrasound or MRI is typically used at baseline and then repeated periodically, to track the lesion and guide timing of any intervention.

Myth #10: "It's better to wait until my child is older before treating a vascular birthmark."

Fact: While it is true that some haemangiomas can be safely observed, delaying treatment is not always the right approach.

For haemangiomas in high-risk locations, the window for effective treatment is early, ideally within the first few weeks to months of life, when the lesion is still in its growth phase and most responsive to propranolol. 

For vascular malformations, early treatment can prevent complications from worsening over time. Malformations do not resolve spontaneously, and some will enlarge progressively.

Waiting until a child is older may mean managing a more complex lesion with greater risk of complications. The decision on timing should always be made in consultation with a specialist, not based on a general assumption that waiting is safer.

You should seek a specialist assessment if:

• A birthmark is growing rapidly, especially in the first year of life
• It is located near the eye, ear, nose, mouth, or airway
• It is causing pain, bleeding, or ulceration
• It is affecting movement or function of a limb
• You notice swelling, warmth, or a pulsating sensation over the birthmark
• There is a family history of vascular conditions
• You are simply unsure — a specialist assessment will give you clarity and peace of mind

This article is for general informational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional for assessment and management of any medical condition.

Ref: F26

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