Hemangiomas affect 5-10% of all children born in the United States and up to 20% of premature infants, with a higher incidence in girls. Most infantile hemangiomas (IHs) appear within a few weeks of birth, grow rapidly for months to years and eventually involute. "Benign neglect" (no treatment) is therefore recommended by most pediatricians. However, about 1/3 of cases (2-3% of all children born in the US) eventually require medical or surgical interventions for hemangiomas due to blocked vision, problems with breathing, feeding, pain, ulceration, infection, profuse bleeding or disfigurement. None of the interventions are benign. Occasionally, hemangiomas may be fatal.