Novel presentation of harlequin phenomenon (simultaneous cyanotic mottling and frightening pallor [vasospasm] of one limb)

Harlequin phenomenon is a benign, idiopathic, and rapidly autoresolutive skin phenomenon (discoloration of unilateral body), with no need for treatment. A 2 h-old preterm newborn manifested net-like cyanosis of the left half of the body, followed by severe pallor of the left leg. It normalized in 15 min without any significant intervention. Correct identification of this frightening but transient benign condition and its variants is very important so as to reassure parents and to avoid additional diagnostic procedures and unnecessary treatments.