Mini-Review on the Harlequin Syndrome—A Rare Dysautonomic Manifestation Requiring Attention

Abstract

Harlequin syndrome (HS) is a rare autonomic disorder. The causes and risk factors of the disease are not fully understood. Some cases of HS are associated with traumatic injuries, tumors, or vascular impairments of the head. Symptoms of HS can also occur in some autoimmune disorders, ophthalmic disorders, sleep disorders, and with certain organic lesions. In this context, a thorough review of the pathophysiology of HS in relation to neurological, ophthalmological, and dermatological conditions is necessary. In this mini-review, we aim to review the pathophysiological changes and underlying mechanisms in primary and secondary HS. Additionally, we discuss possible management approaches for patients with HS in light of the discussed pathological mechanisms. The main symptoms of HS that are correlated with autonomic nervous system impairments include sudden unilateral flushing of the face, neck, chest, and rarely arm, with concurrent contralateral anhidrosis. Despite reported co-occurring syndromes (such as cluster headaches), several studies have shown that HS could frequently overlap with other syndromes that are disruptive to the idiopathic nerve pathways. HS usually does not require any medical treatment. In some severe cases, symptomatic treatments could be needed. However, total symptomatic relief may not be achieved in many cases of HS. We therefore suggest an approach to comprehensive management of HS, which may lead to better long-term control of HS.

What can a thermal imaging camera tell you? Idiopathic Harlequin Syndrome

“…autonomic fibre damage, the face is pale, cool and with decreased sweating, while on the opposite side it is red, normally warm and with normal or increased sweating. Symptoms last from several minutes to several hours, and disappear spontaneously [1][2][3][4][5].…”

“…1) [4]. Making a diagnosis requires a thorough differential diagnosis (imaging of the brain, cervical spinal cord, lungs, carotid arteries) aimed at excluding secondary causes [2,4,5].…”

Harlequin Syndrome Related to Perioperative Intercostal Blockade: A Case Report

“…Causes of secondary Harlequin syndrome include surgical trauma, neoplasms, and pharmacological causes. 5 Even though the syndrome is rare, it is pertinent for the clinician to be aware of it, because although it resembles Horner syndrome, it is both distinguishable and, in most cases, transient. In relation to local anesthetics, the syndrome has been described on multiple occasions as a side effect of blocks near the spine (ie, paravertebral, epidural, or interscalene), [6][7][8] but the syndrome has only once been described in relation to intercostal nerve blockade.…”

Sarcoidosis-Associated Sensory Ganglionopathy and Harlequin Syndrome: A Case Report

“…Harlequin syndrome is a rare disorder of the autonomic nervous system that was first described by Lance et al in 1988 [ 10 ]. It is characterized by unilateral flushing and sweating of the face, neck, and upper chest, concurrent with contralateral anhidrosis, an absence of sweating [ 11 ]. The incidence is unknown, as only sporadic case reports are presented in the literature [ 12 ].…”

“…In the case of T1 sympathetic fiber involvement, occulosympathetic innervation will be affected and ipsilateral Horner syndrome may be seen [ 12 ]. Regarding its etiology, half of the cases are due to either structural or iatrogenic causes, while the other half are idiopathic [ 11 ]. Only a few authors have raised the possibility of an autoimmune mechanism for Harlequin syndrome [ 13 ].…”