Infantile hemangiomas has a fairly predictable pattern of growth. Most appear during the first weeks of life and grow rapidly (called the proliferative phase) for 6 to 12 months. Then they begin a much slower process of shrinking, or regressing (called the involuting phase), which may take from one to about seven years. Finally, the tumor enters its final, shrunken state (called the involuted phase), after which it will never regrow. Tumor regression is complete in 50% of children by age 5 and in 70% of children by age 7. By the time a child reaches 10 to 12 years of age, involution of the tumor is always complete. Some residual fatty tissue or thin skin may remain after involution.

Rarely hemangioma begins in the womb and presents fully grown at birth, called a congenital hemangioma. There are two forms of congenital hemangioma:
1) rapidly invoulting congenital hemangioma (RICH)
2) non-involuting congenital hemangioma (NICH)

Hemangiomas are three to five times more common in females (especially fair-skinned girls) than in males, and occur more frequently in Caucasian infants than in Asian infants. They are rare in African-American infants.

The incidence of hemangiomas may be as high as 25% in premature infants of a low birth weight (fewer than 1,000 grams). They are also more common in twins.

The search on the cause of infantile hemangioma is actively pursued at the Vascular Biopsy Laboratory at Children's Hospital Boston and Craniofacial Laboratory, Harvard School of Dental Medicine. The findings point to the cause as a mutation in a primitive cell destined to become an endothelial cell. This stem cell may originate in the fetus.

While hemangiomas often grow within the skin, they can also develop in virtually any internal organ, including the liver, gastrointestinal tract, and even the brain.

A tumor near the skin's surface is called a superficial hemangioma. It often looks like a raised bright red patch, sometimes with a textured surface (hence the once-commonly used term "strawberry hemangioma"). Veins radiating from the tumor may also be visible beneath the skin. As the hemangioma begins to or shrink, the red color fades. Usually, the last traces of color are gone by the time the child reaches age 7.

Hemangiomas that grow in the lower layers of the skin, called deep hemangiomas; they appear bruise-like or bluish or may not be visible at all. They are usually found at two to four months of age.

Congenital hemangiomas look different than the more common type that grows after birth. They are large at birth, round or oval and have a grayish cast with prominent veins and may be encircled by a pale halo.

Many parents find it reassuring to see before and after photographs of children who have had a hemangioma similar to their child's. This gives them an idea of what to expect at each stage of the tumor's development or from treatment.

Parents who view these images need to keep in mind that every child is unique, therefore their child's outcome may be different. The child's primary care physician or vascular anomalies specialist is the best source of information about what a particular child's outcome will most likely be.

There are exceptions. A child should be referred to a vascular anomalies specialist if the diagnosis is unclear or if the hemangioma is large, growing rapidly, or at risk of causing endangering or disfiguring complications.

A child who has multiple hemangiomas in the skin should also be evaluated by a vascular anomalies specialist, as this sometimes signifies that there is a hemangioma in an internal organ, such as the liver or gastrointestinal tract. These can be life-threatening and require treatment.

About 5 percent to 10 percent of children with a hemangioma develop an ulcer, typically on the lip or the peri anal or genital region. An ulcer is usually effectively treated with topical antibiotics and frequent cleansing and dressings. Sometimes oral medications, laser treatment, or surgical removal may be necessary. Bleeding, which is rare, can usually be controlled by applying pressure to the area. An ulcer usually heals within a few weeks and does not recur. However, it may result in scarring that requires surgical correction.

Hemangiomas that obstruct an airway or interfere with vision, hearing, or eating require prompt treatment. An infant with a hemangioma in the upper eyelid, even a small one, should be immediately evaluated by a pediatric ophthalmologist (eye doctor), as these can permanently affect the child's vision.

Because of their size or location, some hemangiomas can cause distortion of facial features. To prevent permanent tissue damage and/or subsequent emotional trauma, drug treatment is given to slow the growth and shrink the tumor.

If there is any uncertainty about whether a vascular lesion (birthmark) is a hemangioma or a vascular malformation, ultrasonography, a non-invasive diagnostic tool, usually provides a definitive answer. In some instances, magnetic resonance imaging (MRI) or rarely computed tomography (CT), which are also non-invasive radiological tests, may be necessary to make a diagnosis and determine the extent of the tumor.

If there is any suspicion of a malignancy (cancer), a biopsy should be performed. A biopsy involves removing a small section of tumor tissue for microscopic examination by a pathologist.

Some hemangiomas do require intervention, either because they could be disfiguring or might endanger the child's normal functions or life. These include hemangiomas that are obstructing breathing or vision, and those that are ulcerated or bleed; or that distort facial features.

The usual treatment options for problematic hemangiomas include medications and/or operations. Medications include corticosteroid (given by injection directly into the tumor or taken orally every day) or, if corticosteroid is ineffective, other drugs can be given, such as intravenous vincristine or interferon (given daily by injection under the skin). Rarely, embolization, a procedure in which particles are injected into the blood vessels to stop the blood flow, is used to treat children with complications from a liver hemangioma or to stop bleeding that does not respond to medication.

Excision may be indicated for a well-localized hemangioma in the upper eyelid or obstructing the airway. An operation to remove a disfiguring hemangioma that is not fully involuted is sometimes recommended to spare a child emotional distress. The benefits of an early operation must be carefully weighed against the scarring, which occurs in all surgical procedures.

Laser therapy is not effective for treating hemangiomas and may, in fact, cause scarring. Pulsed-dye laser only lightens the surface color. CO2 laser is useful for removing hemangioma inside the child's airway. Laser therapy is effective for fading telangiectasias that often remain after an infantile hemangioma has involuted.