What causes facial flushing?

Facial Flushing: Causes and Clinical Approach

Facial flushing results from cutaneous vasodilation triggered by multiple mechanisms, with the most common causes being rosacea, medications (particularly niacin, alcohol, and vasodilators), menopausal hot flashes, and emotional triggers, though life-threatening conditions including carcinoid syndrome, pheochromocytoma, mastocytosis, and anaphylaxis must be systematically excluded before attributing symptoms to benign causes. 1, 2, 3

Life-Threatening Causes (Exclude First)

Anaphylaxis

• Anaphylaxis is highly likely if ANY ONE criterion is present: acute onset with skin/mucosal involvement plus either respiratory compromise or reduced blood pressure, two or more organ systems involved rapidly after allergen exposure, or reduced blood pressure after known allergen exposure 1
• Distinguished from other flushing by accompanying urticaria, angioedema, pruritus, and tachycardia 4
• Administer epinephrine 0.3 mg intramuscularly immediately into the mid-outer thigh if suspected—delayed epinephrine increases mortality and risk of hypoxic-ischemic encephalopathy 1
• Do not delay epinephrine while waiting for laboratory confirmation 1

Serious Endocrine and Neoplastic Causes

• Carcinoid syndrome: Measure serum serotonin and urinary 5-hydroxyindoleacetic acid 4, 2
• Pheochromocytoma: Measure plasma-free metanephrine and urinary vanillylmandelic acid 4, 2
• Mastocytosis: Obtain serum tryptase levels 15 minutes to 3 hours after symptom onset (though normal levels do NOT rule out anaphylaxis) 1, 2
• Gastrointestinal tumors (VIPoma), medullary thyroid cancer, renal cell carcinoma, and pancreatic cell tumors should be considered in unexplained cases 4, 5

Common Benign Causes

Rosacea

• Characteristic findings include erythema, telangiectasia, papules, pustules, prominent sebaceous glands, and rhinophyma, with a history of easy facial flushing being a key diagnostic feature 6
• More frequently observed in fair-skinned individuals but occurs in all skin types 6
• Challenging to diagnose in darker skin tones because telangiectasia and facial flushing are difficult to visualize—emphasize hyperpigmentation and burning/stinging symptoms in these patients 6, 7
• More prevalent in women but more severe in men 6
• Often overlooked in children who may present with ocular findings (recurrent chalazia, styes, chronic keratoconjunctivitis, meibomian gland dysfunction) before cutaneous manifestations appear 6, 7
• Children with recurrent styes have increased risk of developing adult rosacea and may develop sight-threatening complications including corneal melting and perforation 7

Medication-Induced Flushing

• Niacin causes flushing (warmth, redness, itching, tingling) as a common side effect that may subside after several weeks of consistent use 8
• Flushing more likely with initiation or dose increases; minimized by bedtime dosing and avoiding alcohol, hot beverages, and spicy foods 8
• Other medications include nicotine, catecholamines, ACE inhibitors, vancomycin, systemic retinoids (isotretinoin), antihistamines, and anticholinergics 6, 4
• Isotretinoin increases Staphylococcus aureus colonization and causes blepharitis—discontinuation leads to improvement 7
• Dupilumab (for atopic dermatitis) causes conjunctivitis, keratitis, and blepharitis in 32-55% of patients 7

Alcohol-Induced Flushing (ALDH2 Deficiency)

• ALDH2*2 genetic variant produces inactive aldehyde dehydrogenase 2 enzyme, preventing acetaldehyde metabolism into acetic acid, causing systemic acetaldehyde accumulation with characteristic flushing, tachycardia, palpitations, and reduced alcohol tolerance 4
• Individuals with ALDH2*2 who continue drinking despite flushing have increased risk of alcohol-associated liver disease—screen for elevated AST/ALT (ratio >1.5), elevated GGT, elevated bilirubin, and macrocytic anemia 4
• Complete alcohol abstinence is the definitive management for ALDH2-deficient individuals 4
• Disulfiram should be avoided as it causes acetaldehyde accumulation, producing severe flushing, dizziness, nausea, vomiting, arrhythmia, dyspnea, and headache 4

Menopausal Hot Flashes

• Common cause of flushing in perimenopausal and postmenopausal women 4, 2
• Diagnosis based on age, timing, and associated symptoms 2

Emotional/Idiopathic Flushing

• Remains a diagnosis of exclusion after systematic work-up excludes organic causes 2, 5
• Beta-blockers (propranolol) have suppressed flushing reactions in some patients, particularly when associated with anxiety 9

Additional Causes to Consider

• Scombroid fish poisoning: Histamine from spoiled fish causes flushing 4
• Mast cell activation syndrome: Rare diagnosis of exclusion with persistent facial flushing as presenting feature 10, 5
• Environmental factors: Reduced humidity, increased wind, drafts, air conditioning, or heating may exacerbate flushing 6

Clinical Pitfalls

• Do not rely solely on tryptase or histamine levels to rule out anaphylaxis 1
• Do not dismiss recurrent styes as benign in children—they may represent early ocular rosacea before facial manifestations 7
• In children with pediculosis palpebrarum (pubic lice) causing blepharitis, consider sexual abuse 7
• If symptoms are not progressive after thorough work-up, advise patients about the apparently benign nature to avoid unnecessary studies or treatments of minimal benefit 2