Harlequin syndrome


A rare condition characterized by flushing and sweating that occurs only on one side of the face and may occur for no apparent reason or in response to such things as heat and exercise.


  • Flushing on one side of face 
  • Sweating on one side of face 
  • Mildly drooping eyelid on affected side


  • Infections –HIV –Tuberculosis –Infectious mononucleosis –Fungal (e.g., histoplasmosis, coccidioidomycosis) –Lung or other abscess –Endocarditis –Osteomyelitis 
  • Neoplasms –Leukemia –Hodgkin's disease and other forms of lymphoma –Solid tumors (e.g. prostate, adrenal, renal, testicular) 
  • Menopause/premature ovarian failure 
  • Hyperthyroidism 
  • Diabetes mellitus (nocturnal hypoglycemia) 
  • GERD 
  • Obstructive sleep apnea 
  • Chronic fatigue syndrome 
  • Anxiety 
  • Pregnancy 
  • Drugs [e.g., antipyretics (most common), antihypertensives, phenothiazines, antiretroviral agents] 
  • Substance abuse (including alcohol) 
  • Orchiectomy 
  • Endocrine tumors –Pheochromocytoma –Carcinoid 
  • Chronic eosinophilic pneumonia 
  • Prinzmetal's angina 
  • Temporal arteritis 
  • Takayasu's arteritis


Urinalysis for 5-HIAA should be done if carcinoid syndrome is suspected. Urine samples may be taken for drug and alcohol screen in all cases in which there is any doubt about drug or alcohol history. Tests for serum FSH and estradiol should be done in patients suspected of having menopause. A 24-hr urine collection for catecholamine should be done for patients suspected of having pheochromocytoma. Serum gastrin tests should be done for patients suspected of having Zollinger-Ellison syndrome. In patients with systemic mastitis or dermatomyositis, a skin biopsy or muscle biopsy can be done. In patients with suspected Cushing's disease, a serum cortisol and cortisol suppression test can be done.