Harlequin Syndrome

Harlequin Syndrome Definition

Harlequin syndrome can be defined as unilateral facial sweating and flushing without the interference of hot weather or an episode of extensive exercise. The degree of facial sweating and flushing differ from case to case. The underlying neurological condition is responsible for this syndrome1.


The pathophysiology of Harlequin syndrome involves reducing sympathetic activity. The reduced sympathetic activity can occur due to lesion development. The lesion may develop due to post surgical sympathectomy that influences idiopathic hyperhidrosis and cause unilateral facial sweating and flushing. The stimulatory factors are gustatory and thermoregulatory stimuli and both have considerable influence.

The medical case history also provides the evidence that a neurovascular compression can be one of the pathophysiologies to influence Harlequin syndrome. Studies also found that Harlequin syndrome can occur without ipsilateral ptosis and miosis. This can occur due to a lesion at the level of the 2nd and 3rd thoracic parts of the vertebral column, in the inter-mediolateral cell column, root or white ramus2,3.


The considerable causes, which can influence Harlequin syndrome are as follows:

  • Injury on Sympathetic Nervous System.
  • The resultant of certain surgical interventions like unilateral endoscopic thoracic sympathectomy and/or endoscopic sympathetic blockade as an adverse event.
  • Patients having tumors on a specific spot or stroke which affect carotid circulation can also cause Harlequin syndrome
  • Prolonged strenuous exercises or hot weather exaggerated Harlequin syndrome


Harlequin syndrome has a sudden onset and rare clinical condition. The unique symptom of this syndrome is unilateral sweating along with facial flushing. The symptoms are restricted only one side and another side of the body is normal. The symptom is idiopathic. Along with this specific symptom, other possible symptoms, which may not be noticeable in every case are:

  • Ptosis (drooping of the upper eyelid)
  • The affected side of the face become red, but another side is normal in color
  • The affected side has burning sensation
  • Fluctuating blood pressure and tendency to hypertension
  • Giddiness
  • The symptom of sweating along with facial flushing extend from head to neck, arm, hand and trunk
  • Ocular Horner’s syndrome may associate with Harlequin syndrome3,4

Case Reports

There are different medical kinds of literature discussed several case reports and analyzing those it has cleared that practically clinical presentations of Harlequin syndrome not same for every case. Some case histories are discussed in this section for detail understanding of the symptomatic description of Harlequin syndrome.

Case I

A woman with 73 years of age described her experiences with Harlequin syndrome. In her 64 years of age, she first observed that uneven flushing in the facial region after extensive work in the garden and she discovered a distinct color change at the left half of the face when she looked her face in the mirror.

No other symptoms she observed. The condition was not worsening during the 10 years, but symptoms reappear in exposure to the sun. First systolic blood pressure becomes high at 68 years of age and further also detected that the size of the pupil is not same in both the eyes. The left eye is smaller than right without ptosis.

Case 2

A women having 58 years of age also described her experiences with Harlequin syndrome. She described four years before when she walked on a sunny day, suddenly she felt giddiness and about to fall down. At that time her daughter provided support by holding her hands. Her daughter noticed that she had to flush and profuse sweating at the left half of the face.

After 1-hour sweating was subsided, but even after 2 hours left half of the face was red. She faced this problem frequently and interfere with their daily working ability. Her left eye became red and watery which cause vision disturbance. Left nostril became obstructed due to excessive secretion and that caused breathing problem. Both eyes have similar pupil size, but an ocular examination found that presence of ptosis.

Numbness extends from left half of the face and that extends from left hand to 6th thoracic rib region of the chest. The muscle strength of the left hands and finger became slight weaker than a right-hand finger. This patient also hypertensive.

Case 3

A 42 years male electrician also shared his case history. He first experienced left the side of the face flushed and sweated without same symptoms aroused on the right side at his 37 years of age during his working hours and the condition repeated after one week when played squash.

The asymmetrical flushing and sweating were only restricted to face and neck regions, whereas symmetry is maintained in hands and trunks. He also reported since five years he had mild to moderate retro-orbital headaches, his blood pressure is normal2.


  • Pupillary dilatation is checked with cocaine 5% eye drops for confirming an ocular Horner’s syndrome.
  • Brain and spinal cord imaging
  • Computed tomography (CT) of the brain and thoracic spine
  • MRI of the cervical and thoracic spinal cord
  • Infrared thermography used to check the difference of the temperature of both the side. The affected side temperature is warmer than the non-affected side.
  • Digital subtraction angiography (DSA) to check the internal or external carotid circulations.
  • Increased pulsation on the affected side
  • Qualitative sweating assessment by using alizarin powder that can change color in contact with moist
  • Quantitatively sweating assessment by measuring evaporation of sweat from the forehead. The sweating amount is more at the forehead, cheek and comparatively lesser amount at the chin.

Precisely the diagnosis of Harlequin syndrome procedure requires duplex ultrasonography, scintigraphy, autonomic testing, neurological examination and MRI5,6,7.


Usually, no treatment require for treating Harlequin syndrome, as it is not considered as a serious health issue. The condition is benign nature. Certain accompanied condition requires regulating like thyroid gland functioning, autonomous adenoma. Patient specific treatment approaches include Contralateral sympathectomy.

It is necessary to spot the lesion present on the impaired nerve before conducting a surgical intervention.

A stellate ganglion block is another option to control Harlequin syndrome. This procedure is applied , when surgical intervention not acceptable for the patient condition. A local anesthetic is administered in stellate ganglion block. This technique is novel and effective to reduce the intensity of the symptoms of the harlequin syndrome and also reduce the duration4,5.


Harlequin Syndrome photos 4

Harlequin Syndrome Harlequin Syndrome pics 3 Harlequin Syndrome photos


The prognosis of Harlequin Syndrome is moderate to poor, as it provides awkwardness and discomfort. But no associated complications are present in Harlequin Syndrome5.


  1. Sribnick EA, Boulis NM; Treatment of Harlequin syndrome by costotransversectomy and sympathectomy: case report. Neurosurgery. 2011 Jul;69(1):E257-9. doi: 10.1227/NEU.0b013e3182186829.
  2. JAMES W LANCE, PETER D DRUMMOND, SIMON C GANDEVIA, JOHN G L MORRISt; Harlequin syndrome: the sudden onset of unilateral flushing and sweating; Harlequin syndrome: the sudden onset of unilateral flushing and sweating; Journal of Neurology, Neurosurgery, and Psychiatry 1988;51:635-642
  3. Wilson WC. Observations relating to the innervation of the sweat glands of the face. Clin Sci 1936;2;273-286.
  4. Drummond PD, Lance JW. Facial flushing and sweating mediated by the sympathetic nervous system. Brain 1987;110:793-803.
  5. Dr. Shweta U Shah; What is Harlequin Syndrome?: Treating Harlequin Syndrome; https://brain-health-neurology.knoji.com/what-is-harlequin-syndrome-treating-harlequin-syndrome/
  6. Gunnar Wasner, Rainer Maag, Janne Ludwig, Andreas Binder, Jörn Schattschneider, Robert Stingele and Ralf Baron; Harlequin syndrome – one face of many etiologies; Nature Clinical Practice; Neurology (2005) 1, 54-59; doi:10.1038/ncpneuro0040  Received 13 June 2005 | Accepted 18 August 2005
  7. Haxton HA. Gustatory sweating. Brain 1948;71: 16-25.

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