INTRODUCTION
Infantile hemangiomas (IHs) are a common childhood tumor occurring in 5-10% of children and present as selflimiting vascular endothelial tumors, often involving the head and neck.1 Present at birth followed by a proliferative growth phase and subsequent stabilization or spontaneous involution over several years, IHs are mostly focal and solitary with rare involvement of extracutaneous sites including the liver, pancreas, thymus, and spleen.2 The overall incidence of IH is 22-30% in preterm infants with a birthweight less than 1 kg, with female, white, non-Hispanic newborns more likely to be diagnosed.3 The proliferative phase commonly occurs in the neonatal or early infancy periods due to the rapid division of endothelial cells. Although the precise mechanisms by which proliferation and involution occur are not completely understood, fibroblast growth factor and vascular endothelial growth factors have been identified as important components.1
Without intervention, complete resolution occurs in about 49% of patients by age 5 and 72% of patients by age 7.6 Although
IHs are classified by depth into superficial, deep, or mixed categories. Superficial IHs manifest in the superficial dermis and are bright red in color. Deep IHs are involved in the dermis and hypodermis, often appearing blue. Mixed IHs take on characteristics of both subtypes. Similarly, IHs can also be classified by morphology such as localized, segmental, or indeterminate. Localized IHs are round with discrete borders while segmental IHs are larger, patchy, and encompass broader regions.4 These features aid in the development of the Hemangioma Activity Score (HAS) which assesses disease severity and treatment response based on color profiles, depth, and morphology. While there is no universal scoring system, the HAS system is routinely used to follow treatment response over time.5
Without intervention, complete resolution occurs in about 49% of patients by age 5 and 72% of patients by age 7.6 Although
