Harlequin syndrome is a rare nerve condition that causes one side of the face and sometimes the upper body to turn red and sweat while the other side remains normal. It often affects children and young adults, but can be seen at any age. Harlequin Syndrome occurs when the sympathetic nerves on one side of the face fail to work properly. The sympathetic system is part of the autonomic nervous system, which controls automatic body functions like sweating and blood vessel size. In Harlequin Syndrome, damage or disruption in these nerves causes one half of the face to flush and sweat normally while the other half does nothing. Over time, people learn which triggers—such as warm weather, exercise, spicy food, or strong emotions—cause these red and sweaty episodes. Although it looks alarming, Harlequin Syndrome is usually harmless to overall health, but it can affect confidence and comfort.
Harlequin syndrome happens when the body’s automatic nerve signals to sweat glands and blood vessels get mixed up on one side. Normally, when you exercise or get hot, both sides of your face and body respond the same way. In Harlequin syndrome, one side “plays along,” getting red and sweaty, while the other side stays pale and dry. This mismatch is due to a problem in the sympathetic nervous system—the part of the nervous system that controls sweating, blood vessel widening, and other “automatic” actions.
Types of Harlequin Syndrome
Although Harlequin syndrome is essentially one condition, doctors describe it based on how and when it appears:
Congenital (Present at Birth):
Seen from early childhood.
Often linked to minor birth-related nerve damage.
Acquired (Develops Later):
Begins in adolescence or adulthood.
May follow surgery, injury, or certain diseases.
Idiopathic (Unknown Cause):
No clear reason is found.
Symptoms appear without injury or illness.
Secondary to Other Conditions:
Occurs along with diseases like diabetes, multiple sclerosis, or tumors.
Treating the main disease can improve Harlequin symptoms.
Possible Causes
Birth Trauma: Pressure on nerves during delivery.
Neck Surgery: Injury to sympathetic nerves.
Chest Surgery: Damage near the upper ribs.
Tumors: Benign or malignant growth pressing on nerves.
Stroke: Disruption of nerve pathways in the brain.
Multiple Sclerosis: Autoimmune attacks on nerves.
Diabetes: Long-term high blood sugar harming nerves.
Trauma: Blunt force or penetrating injury to neck/chest.
Autoimmune Diseases: Conditions like lupus attacking nerves.
Infections: Shingles or Lyme disease affecting nerves.
Spinal Cord Lesions: Damage near upper spinal levels.
Thoracic Outlet Syndrome: Nerve compression between collarbone and first rib.
Peripheral Neuropathy: Generalized nerve damage from toxins or drugs.
Idiopathic: No identifiable reason.
Horner’s Syndrome Overlap: Sometimes occurs together with Horner’s signs.
Cluster Headaches: Severe headaches linked with facial flushing.
Medication Side Effects: Drugs affecting nerve signaling.
High-Intensity Exercise: Unmasks underlying nerve imbalance.
Cold Exposure: Can trigger asymmetric flushing.
Emotional Stress: Strong emotions may provoke uneven sweating.
Common Symptoms
One-Sided Facial Redness: Flushing only on one cheek.
Dryness on One Side: Lack of sweat where opposite side sweats.
Sweating on the Other Side: Excessive sweat on the healthy side.
Warm Sensation: Feeling of heat on the flushed side.
Cool Sensation: The pale side may feel cool.
Asymmetrical Sweating: Noticeable imbalance during exercise.
Uneven Blushing: During embarrassment or stress.
Headache: Mild headache on the flushed side.
Eye Redness: Sometimes one eye turns red.
Constricted Pupil (Rare): Small pupil on the pale side.
Drooping Eyelid (Rare): Mild eyelid droop on one side.
Chest Flushing: Extension of symptoms to upper chest.
Neck Sensation Changes: Tingling or numbness near affected nerves.
Skin Temperature Difference: Measurable with a thermometer.
Visual Difference: Side-by-side photos show stark contrast.
Diagnostic Tests
Physical Examination
Observation of Flushing: Watch face during exercise or heat.
Symmetry Check: Compare sides in the mirror at rest and after activity.
Gentle Skin Pinch: Assess sweat response by looking for sweat drops.
Thermal Palpation: Feel skin temperature differences with your hand.
Manual Tests
Starch-Iodine Test: Iodine applied to skin, starch powder sprinkled; sweat turns the area dark.
Minor’s Test: Similar to starch-iodine but maps sweat patterns.
Skin Scratch Test: Scratch skin lightly; observe if one side doesn’t flush.
Provocative Posture Test: Change posture to stress sympathetic nerves.
Lab & Pathological Tests
Blood Glucose Test: Rule out diabetic neuropathy.
Autoimmune Panel: Detect lupus or other autoimmune markers.
Infectious Disease Screen: Test for Lyme, shingles, or other infections.
Hormone Levels: Check thyroid and adrenal functions.
Electrodiagnostic Tests
Sympathetic Skin Response (SSR): Measure electrical changes in sweat glands.
Nerve Conduction Study (NCS): Test speed of nerve signals in neck region.
Electromyography (EMG): Check muscle electrical activity near affected nerves.
Heart Rate Variability (HRV): Indirect measure of autonomic nervous system balance.
Imaging Tests
Magnetic Resonance Imaging (MRI) of Neck/Chest: Look for tumors or lesions.
Computed Tomography (CT) Scan: Detailed view of bony structures compressing nerves.
Ultrasound of Carotid Sheath: Assess blood vessel and nerve anatomy.
Positron Emission Tomography (PET) Scan: Rarely, to identify small tumors or inflammation.
Non-Pharmacological Treatments
Below are therapies and lifestyle approaches backed by clinical experience or small studies. Each entry explains what it is, why it helps, and how it works.
Trigger Avoidance
Description: Identify and avoid things (heat, exercise) that cause flushing.
Purpose: Reduce episodes.
Mechanism: Prevents sympathetic over-activation.
Cool Environment
Description: Stay in air-conditioned rooms or use cool fans.
Purpose: Keeps body temperature down.
Mechanism: Lowers overall sympathetic drive.
Cold Packs
Description: Apply on one side of the face when symptoms start.
Purpose: Rapidly constricts blood vessels.
Mechanism: Local vasoconstriction reduces redness.
Biofeedback Therapy
Description: Learn to control sweating via monitoring devices.
Purpose: Gain voluntary control over sweating.
Mechanism: Trains brain to modulate autonomic responses.
Relaxation Techniques
Description: Deep breathing, progressive muscle relaxation.
Purpose: Reduce stress-induced flushing.
Mechanism: Activates parasympathetic (“rest”) system.
Meditation and Mindfulness
Description: Guided practices focusing on calm awareness.
Purpose: Lower emotional triggers.
Mechanism: Down-regulates sympathetic outflow.
Acupuncture
Description: Inserting fine needles at specific points.
Purpose: Balance autonomic nerves.
Mechanism: May modulate nerve signaling.
Chiropractic Adjustment
Description: Spinal adjustments to ease nerve pressure.
Purpose: Improve nerve function.
Mechanism: Restores normal sympathetic pathways.
Physical Therapy
Description: Gentle neck and shoulder exercises.
Purpose: Alleviate nerve compression.
Mechanism: Reduces mechanical irritation of sympathetic chain.
Massage Therapy
Description: Light massage of neck muscles.
Purpose: Relieve tension.
Mechanism: Improves local circulation and nerve function.
Yoga
Description: Gentle poses and breathing.
Purpose: Enhance relaxation.
Mechanism: Shifts balance toward parasympathetic control.
Hydrotherapy
Description: Switching between warm and cool water on face.
Purpose: Train blood vessels to react less strongly.
Mechanism: Trains vascular autoregulation.
Mirror Biofeedback
Description: Watching your face during triggers.
Purpose: Increase awareness of early signs.
Mechanism: Allows early self-intervention.
Cognitive Behavioral Therapy (CBT)
Description: Talking therapy to change stress reactions.
Purpose: Reduce anxiety-driven flushing.
Mechanism: Alters thought patterns that trigger sympathetic surges.
Stress-Management Counseling
Description: Professional strategies to cope with stress.
Purpose: Long-term reduction in episodes.
Mechanism: Teaches coping skills that dampen nerve overactivity.
Avoiding Spicy Foods
Description: Limit chili, hot sauce, pepper.
Purpose: Prevent gustatory flushing.
Mechanism: Capsaicin activates sympathetic reflex.
Wear Loose Clothing
Description: Choose breathable, non-restrictive fabrics.
Purpose: Reduce unnecessary heat retention.
Mechanism: Helps maintain stable body temperature.
Hydration
Description: Drink adequate water.
Purpose: Supports normal sweat production.
Mechanism: Maintains fluid balance and thermoregulation.
Gradual Warm-Up Before Exercise
Description: Slowly ramp up activity intensity.
Purpose: Prevent sudden sympathetic spikes.
Mechanism: Allows gradual vascular adjustment.
Cold Beverage Preparation
Description: Sip chilled water during exertion.
Purpose: Locally cool facial skin from inside.
Mechanism: Systemic cooling reduces sympathetic tone.
Drug Treatments
These medications have been used off-label or in small case series for Harlequin Syndrome.
Glycopyrrolate
Class: Anticholinergic
Dosage & Time: 1–2 mg orally, once or twice daily.
Purpose: Reduce sweating.
Mechanism: Blocks acetylcholine on sweat glands.
Side Effects: Dry mouth, blurred vision, constipation.
Oxybutynin
Class: Antimuscarinic
Dosage & Time: 5 mg orally, once daily.
Purpose: Decrease facial sweating.
Mechanism: Inhibits muscarinic receptors in sweat glands.
Side Effects: Dry eyes, urinary retention.
Botulinum Toxin Type A
Class: Neurotoxin
Dosage & Time: 2.5–5 U injections into affected area every 3–6 months.
Purpose: Block sweat release locally.
Mechanism: Prevents acetylcholine release at nerve endings.
Side Effects: Local weakness, bruising.
Clonidine
Class: Alpha-2 agonist
Dosage & Time: 0.1 mg orally, twice daily.
Purpose: Reduce sympathetic outflow.
Mechanism: Activates central alpha-2 receptors to lower sympathetic tone.
Side Effects: Drowsiness, dry mouth, low blood pressure.
Propranolol
Class: Beta-blocker
Dosage & Time: 10–20 mg orally, three times daily.
Purpose: Control flushing from emotional triggers.
Mechanism: Blocks beta-adrenergic receptors that mediate blood vessel dilation.
Side Effects: Fatigue, slow heart rate.
Topical Aluminum Chloride
Class: Antiperspirant agent
Dosage & Time: Apply nightly to affected area.
Purpose: Reduce local sweating.
Mechanism: Blocks sweat gland ducts.
Side Effects: Skin irritation.
Hydrocortisone Cream
Class: Corticosteroid
Dosage & Time: Apply twice daily to injected sites (after botox).
Purpose: Reduce local irritation.
Mechanism: Anti-inflammatory.
Side Effects: Skin thinning with long use.
Antihistamines (e.g., Cetirizine)
Class: H1 antagonist
Dosage & Time: 10 mg once daily.
Purpose: Some relief of flushing.
Mechanism: Blocks histamine-mediated vasodilation.
Side Effects: Drowsiness (less with 2nd generation).
Topical Clonidine Gel
Class: Alpha-2 agonist topical
Dosage & Time: Applied to face twice daily.
Purpose: Reduce local sympathetic activity.
Mechanism: Local vasoconstriction.
Side Effects: Possible skin irritation.
Capsaicin Cream
Class: Desensitizing agent
Dosage & Time: Apply 0.025% cream three times daily.
Purpose: Decrease nerve responsiveness.
Mechanism: Depletes substance P in nerves.
Side Effects: Initial burning sensation.
Dietary Molecular & Herbal Supplements
Though evidence is limited, these supplements may support nerve health and modulate inflammation.
Omega-3 Fish Oil (1 g/day)
Function: Anti-inflammatory.
Mechanism: Produces less inflammatory eicosanoids.
Alpha-Lipoic Acid (600 mg/day)
Function: Nerve antioxidant.
Mechanism: Scavenges free radicals in nerves.
Vitamin B12 (1000 µg/day)
Function: Supports nerve myelin.
Mechanism: Cofactor for myelin synthesis.
Acetyl-L-Carnitine (500 mg twice daily)
Function: Nerve repair support.
Mechanism: Supports mitochondrial energy.
Curcumin (500 mg twice daily)
Function: Anti-inflammatory.
Mechanism: Inhibits NF-κB pathway.
Ginkgo Biloba (120 mg/day)
Function: Improves microcirculation.
Mechanism: Antioxidant and vasodilator.
Magnesium (300 mg/day)
Function: Nerve conduction stability.
Mechanism: Regulates ion channels.
Coenzyme Q10 (100 mg/day)
Function: Mitochondrial support.
Mechanism: Part of electron transport chain.
Ashwagandha (300 mg/day)
Function: Adaptogen for stress.
Mechanism: Modulates HPA axis.
L-Arginine (2 g/day)
Function: Promotes blood flow.
Mechanism: Nitric oxide precursor.
Green Tea Extract (250 mg/day)
Function: Antioxidant support.
Mechanism: High in polyphenols.
Resveratrol (100 mg/day)
Function: Anti-inflammatory.
Mechanism: Activates SIRT1 pathway.
Vitamin D3 (2000 IU/day)
Function: Immune modulation.
Mechanism: Regulates nerve growth factors.
Zinc (15 mg/day)
Function: Nerve repair cofactor.
Mechanism: Cofactor for numerous enzymes.
Boswellia Serrata (300 mg twice daily)
Function: Inhibits inflammatory mediators.
Mechanism: Blocks 5-lipoxygenase.
Regenerative / Stem-Cell-Related Drugs
Experimental approaches aimed at nerve regeneration or immune modulation.
Intravenous Immunoglobulin (IVIG, 2 g/kg over 2 days)
Function: Modulates autoimmune components.
Mechanism: Provides antibodies that neutralize auto-reactive factors.
Mesenchymal Stem Cell Infusion (100 million cells)
Function: Promote nerve repair.
Mechanism: Secrete growth factors and modulate immunity.
Erythropoietin (40,000 IU weekly)
Function: Neuroprotective.
Mechanism: Activates anti-apoptotic pathways in nerves.
Nerve Growth Factor (NGF) Peptides (5 µg intranasal daily)
Function: Stimulate nerve growth.
Mechanism: Binds TrkA receptors on neurons.
Autologous Platelet-Rich Plasma (PRP) Injection
Function: Delivers concentrated growth factors.
Mechanism: Releases PDGF, VEGF to support repair.
Thymosin Beta-4 (1.6 mg daily)
Function: Promotes cellular migration and repair.
Mechanism: Regulates actin and cell motility.
Surgical Procedures
When conservative measures fail, a surgeon may intervene.
Contralateral Sympathectomy
Procedure: Cut sympathetic chain on healthy side.
Why: Balances heat and sweat responses.
Stellate Ganglion Block
Procedure: Inject anesthetic near cervical ganglion.
Why: Temporarily blocks sympathetic signals.
Endoscopic Thoracic Sympathectomy
Procedure: Remove part of T2–T3 sympathetic chain.
Why: Permanent relief of unilateral symptoms.
Nerve Grafting
Procedure: Replace damaged segment with donor nerve.
Why: Restore normal nerve conduction.
Microvascular Decompression
Procedure: Relieve blood vessel pressure on nerve.
Why: Reduce mechanical irritation of sympathetic chain.
Prevention Strategies
Simple steps to lower risk of triggering Harlequin episodes:
Keep living and working spaces cool.
Avoid intense direct sunlight.
Warm up slowly before exercise.
Choose breathable, light clothing.
Stay well‐hydrated throughout the day.
Learn stress‐management techniques.
Limit spicy or very hot foods.
Take scheduled breaks during physical activity.
Monitor and record triggers in a diary.
Use sunblock to reduce facial heat absorption.
When to See a Doctor
Consult a healthcare professional if you experience:
New or worsening one-sided facial redness or sweating.
Pain, numbness, or weakness in the face or neck.
Flushing accompanied by chest pain, shortness of breath, or fainting.
Sudden onset after neck trauma or surgery.
Concerns about underlying tumors or nerve damage.
Foods to Eat and Avoid
Eat:
Cooling fruits (watermelon, cucumber).
Whole grains (brown rice, oats).
Lean proteins (chicken, fish).
Leafy greens (spinach, kale).
Yogurt (probiotics, cooling).
Nuts and seeds (magnesium source).
Herbal teas (peppermint, chamomile).
Berries (antioxidants).
Legumes (steady energy).
Coconut water (electrolytes).
Avoid:
Spicy chilies and hot sauces.
Caffeinated drinks (coffee, energy drinks).
Alcoholic beverages.
Very hot soups or stews.
Excessive sugar (energy spikes).
Heavy red meats (heat-generating).
Fried or greasy foods.
High-salt snacks (thirst and sweat).
Very hot coffee or tea.
Excessive simple carbohydrates.
Frequently Asked Questions
What causes Harlequin Syndrome?
It most often stems from damage to the sympathetic nerves on one side of the face, from surgery, trauma, or tumors.Is it dangerous?
Harlequin Syndrome itself isn’t life-threatening, but underlying causes may need evaluation.Can it go away on its own?
Sometimes mild cases improve without treatment, but nerve injuries often persist.Will I always sweat on only one side?
Yes, unless treated with medications or surgery, the asymmetry remains.Does it affect other body parts?
Rarely. It mainly involves the face and upper neck.Is there a cure?
There’s no universal cure, but treatments can reduce symptoms.Can children get it?
Yes, though it’s more common in adults after injury or surgery.How is it diagnosed?
Doctors examine your response to heat or exercise and may use nerve imaging.Are tests needed?
MRI or CT scans can check for tumors or structural nerve damage.Will medications fix it permanently?
Most drugs offer temporary relief; some require ongoing use.What are treatment risks?
Anticholinergic drugs can cause dry mouth, blurred vision; surgery risks include nerve damage.Is surgery the best option?
Surgery is reserved for severe cases when other treatments fail.Can I drive or work normally?
Yes, Harlequin Syndrome doesn’t usually impair daily activities.Does it affect emotions?
Flushing can be embarrassing but doesn’t directly change mood.Are online support groups helpful?
Yes—sharing experiences can improve coping and find new tips.
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: August 05, 2025.
