The incidence and significance of birthmarks in a cohort of 4,641 newborns.

An unselected cohort of 4,641 newborns was ascertained prospectively for the purpose of detecting any cutaneous lesion. These were catalogued into pigmented lesions, vascular lesions, and miscellaneous lesions. Several important findings were elucidated: congenital nevocellular nevi are speckled at their borders; no white newborn in the study had more than one café au lait mark; a hypopigmented tuft of hair was seen in one infant with tuberous sclerosis but is found more commonly in normal individuals; a previously undescribed lesion called zosteriform melanocytic nevus was seen as a normal pigmentary variant in blacks; and hypopigmented macules seen at birth are seen primarily in normal infants. It is hoped that these findings will allow the pediatrician and dermatologist to offer more meaningful prognostic information to their patients.