Infantile hemangiomas: how common are they? A systematic review of the medical literature.

No published prospective studies have been published for several decades examining the incidence of hemangiomas. Older studies were performed before the delineation of "hemangiomas" from other vascular birthmarks was well-established. The objective of our study is to critically re-examine the literature reporting the incidence of infantile hemangiomas to determine if the true incidence is actually known. We performed both an electronic database search and hand search of the medical literature on the natural history of hemangiomas in full-term newborns and infants. A total of seven articles were found comprising two study populations: newborns <2 weeks of age and infants over the age of 2 weeks. All studies included samples sizes >500 patients including both hospital-based and primary care settings. Study designs ranged from retrospective chart reviews to cross-sectional cohort studies. Descriptive nomenclature was not uniform between studies, and all had methodologic limitations including problems of definition and study design. Studies estimating the true incidence of infantile hemangiomas are all many decades old and have significant methodologic issues limiting their ability to determine hemangioma incidence. Future studies in primary care settings using the currently accepted classification schema of vascular birthmarks may more accurately define the incidence and potential impact of this common vascular tumor of infancy.