Halo scalp ring in a premature newborn and review of the literature.

Unusually prolonged pressure on the scalp by the cervical os during or before the delivery may result in a distinctive pattern of annular alopecia that has been referred to as halo scalp ring. This rare form of hair loss is most commonly a temporary, non-scarring process that is attributed to caput succedaneum. We report a new case of halo scalp ring in a premature newborn. Review of previously reported cases suggests that prematurity is an important, previously unrecognized, risk factor for developing a halo scalp ring.