To provide incidence data based on ethnicity, prematurity, and body site for vascular, pigmented, and other common congenital cutaneous findings; to compare these results with previously published prospective studies; and to define updated nomenclature, classification, clinical course, and prognostic factors for the pediatric practitioner to promote a better understanding of benign versus more worrisome birthmarks.

This prospective study enrolled 594 infants in San Diego, California. Cutaneous examination was performed by pediatric dermatologists in the first 48 hours of life, with subsequent longitudinal contact via telephone, and repeat evaluations if any new lesions were reported by parents. Incidence rates were calculated by ethnicity and prematurity status.

The most common vascular lesion was nevus simplex (83%), followed by infantile hemangioma (4.5% by age 3 months), capillary malformation (0.3%), and rapidly involuting congenital hemangioma (0.3%). Pigmented lesions seen at birth included dermal melanocytosis (20%), congenital melanocytic nevi (2.4%), and café au lait macules (2%). Other common skin findings were erythema toxicum neonatorum (7%), milia (8%), and sebaceous gland hyperplasia (42.6%).

This study of congenital cutaneous lesions, using current nomenclature and data acquired by pediatric cutaneous lesion experts, provides data regarding the role of race and ethnicity in the incidence of birthmarks, and provides valid data on the prevalence of infantile hemangioma.