Intractable vascular autonomic dysregulation (Harlequin phenomenon) in two brothers: another indication for propranolol?

Vascular autonomic dysregulation, in the most extreme presentation known as Harlequin phenomenon, is a rare condition. It manifests as a sudden and brief paroxystic change in skin color, resulting in two different colors on the body. It is supposed that this condition occurs due to a vasomotor instability. This again is caused by sympathetic disautonomy, which is a consequence of hypothalamic peripheral vascular tone control immaturity in the newborn. Typically, there is spontaneous regression. We describe two brothers who both had this condition in their first life years. Clinical symptoms included frequent attacks of discoloration of extremities (up to four times per day) accompanied with terrifying crying fits, interpreted by the parents as pain. These patients were treated with propranolol, a nonselective beta-blocker, resulting in improvement of symptoms: only occasional attacks were seen. Beta-blockers act on (1)-adrenoceptors in the heart, thereby preventing the positive chronotropic and inotropic effects mediated by these receptors. We hypothesize that propranolol, which is very lipophilic and therefore also acts on -receptors of the central nervous system, acts on the sympathetic system.