Harlequin syndrome (HS) was first described by Lance in 1988 [1], defined by unilateral facial flushing and sweating with contralateral anhidrosis. This rare syndrome is caused by dysfunction of vasodilatory and sudomotor sympathetic fibers originating from the stellate ganglion or the superior cervical ganglion [2].

We report three cases of Harlequin syndrome, to highlight the originality of its “crossed” symptoms and to improve medical knowledge of this condition.