In a newborn, Harlequins skin change is due to

HARLEQUIN COLOR CHANGEA rare but dramatic vascular event, harlequin color change occurs in the immediate newborn period and is most common in low bihweight infants. It probably reflects an imbalance in the autonomic vascular regulatory mechanism. When the infant is placed on 1 side, the body is bisected longitudinally into a pale upper half and a deep red dependent half. The color change lasts only for a few minutes and occasionally affects only a poion of the trunk or face. Changing the infant's position may reverse the pattern. Muscular activity causes generalized flushing and obliterates the color differential. Repeated episodes may occur but do not indicate a permanent autonomic imbalance.Ref: Nelson textbook of Paediatrics; 20th edition; Chapter 647; Diseases of the Neonate