Infantile hemangiomas are the most common benign tumors of infancy, occurring in up to 10% of infants, with up to 50% involving the head and neck. Precursors may be present at birth, evolving into a more classic appearance within the first few months of life. Usually, infantile hemangiomas grow rapidly during the first few weeks of life. This initial proliferative phase typically peaks as early as 2 months of age. This is followed by a steady state lasting months, depending on the hemangioma type, followed by gradual involution over several years, with more than 90% completely involuting by age 10. Although infantile hemangiomas involute with time, residual skin changes such as telangiectasia, scarring, atrophy, and fibrosis persist in up to 30% of lesions after involution is complete.

Ulceration occurs in about 5% of hemangiomas and can occur at any location. Ulcerated hemangiomas are painful regardless of location, often become secondarily infected, and leave a scar. Bleeding and ulceration can incorrectly cause or increase concern for possible physical abuse; however, their characteristic development in early infancy and typical regression should help differentiate them from the former. Ulceration is of particular concern when it involves the periocular, nasal, perioral, or anogenital areas, given regional risk for severe complication. Anogenital ulceration adversely affects diaper changes, urination, and defecation. Only about 1%-2% of hemangiomas involve the genitalia. Such hemangiomas of the urethra, the labia, hymen, vulva, or perihymenal area may raise concern for sexual abuse. When extensive ulceration is present, there may be concern that these represent perineal burns. Knowledge of the clinical appearance and natural course of untreated hemangiomas may help prevent misdiagnosis.

Segmental infantile hemangiomas raise concern for regional abnormalities. If the anogenital area is involved in a segmental fashion, evaluation for associated anomalies associated with the synonymous LUMBAR syndrome (lower body hemangioma, lipoma, or other cutaneous anomalies, urogenital anomalies, myelopathy, bony deformities, anorectal and arterial anomalies, and renal anomalies), SACRAL syndrome (spinal dysraphism, anogenital anomalies, cutaneous anomalies, renal and urologic anomalies, associated with angioma of lumbosacral localization), or PELVIS syndrome (perineal hemangioma, external genitalia malformations, lipomyelomeningocele, vesicorenal abnormalities, imperforate anus, and skin tags) should ensue.