Flushing: What It Means and What Causes It

What flushing means medically

In medical terms, flushing is transient vasodilation: the small blood vessels in the skin widen, more blood flows through them, and the skin turns red and feels warm or hot. It usually affects the "blush area" (face, ears, neck and upper chest) because the blood vessels there are close to the surface and respond strongly.

People describe the flushing sensation as heat rising up the chest and face, sometimes with tingling, burning or itching. An episode usually lasts from a few seconds to about 30 minutes.

Flushing is different from a rash: it comes and goes, has no bumps or scaling, and the skin returns to normal between episodes. Persistent redness is called erythema.

Wet vs dry flushing

Common causes of flushing

Everyday triggers

• Emotion: embarrassment, anger or stress cause blushing. See blushing.
• Heat: hot weather, hot showers, saunas and hot drinks.
• Exercise.
• Spicy food: capsaicin in chili peppers.
• Fever.

Alcohol

Alcohol widens blood vessels in many people. A strong, fast flush after small amounts of alcohol, often with nausea and a rapid heartbeat, is the alcohol flush reaction. It is common in people of East Asian ancestry, and is caused by an inherited variant of the enzyme ALDH2 that leads to a build-up of acetaldehyde. People with this reaction have a higher risk of esophageal cancer if they drink regularly.

Menopause hot flashes

Hot flashes affect most women around menopause. A wave of heat spreads over the upper body for 1 to 5 minutes, often with sweating, palpitations and then chills. They can continue for several years. Men having hormone treatment for prostate cancer can have the same symptom.

Rosacea

Rosacea causes easy flushing of the central face, with persistent redness, visible blood vessels and sometimes acne-like bumps. Triggers include sun, heat, alcohol, spicy foods and stress.

Flushing as a medication side effect

Flushing is one of the most common drug side effects. Medicines that can cause it include:

• Niacin (vitamin B3) for cholesterol: flushing within 15 to 30 minutes of a dose, usually fading as you get used to it
• Calcium channel blockers (such as nifedipine and amlodipine) and nitrates (such as nitroglycerin)
• Sildenafil, tadalafil and similar drugs for erectile dysfunction
• Opioids, which release histamine
• Vancomycin given too quickly into a vein ("red man" or vancomycin flushing syndrome)
• Corticosteroids, especially high-dose
• Tamoxifen, raloxifene and drugs that lower sex hormones
• Contrast dye used in scans
• Metronidazole or disulfiram with alcohol, which cause a strong flushing reaction

If a new medicine causes troublesome flushing, ask your doctor or pharmacist. Do not stop prescribed medicine without advice. For niacin, taking it with food, using an extended-release form and, if your doctor agrees, taking aspirin beforehand can reduce flushing.

Less common but serious causes

• Anaphylaxis: sudden flushing or hives with breathing difficulty or a drop in blood pressure after a food, sting or drug.
• Carcinoid syndrome: neuroendocrine tumors, usually with liver spread, release serotonin and other substances. It causes dry flushing (sometimes purple), diarrhea and wheezing.
• Pheochromocytoma: an adrenal tumor that releases adrenaline in bursts, causing headache, sweating and a racing heart. Pallor is more typical than flushing, but flushing can occur.
• Mastocytosis: too many mast cells release histamine, causing flushing, itching, stomach cramps and sometimes fainting.
• Overactive thyroid: constant warmth, sweating, weight loss and tremor.
• Medullary thyroid cancer and some other tumors, rarely.

How doctors find the cause

A doctor will ask what the episodes look like, how long they last, whether you sweat, what you were doing beforehand, which medicines and supplements you take, and about alcohol, diarrhea, wheezing and palpitations. A flushing diary noting food, drink, activities and timing is often the most useful tool.

If a serious cause is suspected, tests may include:

• urine or blood tests for serotonin breakdown products (5-HIAA) for carcinoid syndrome
• blood or urine metanephrines for pheochromocytoma
• serum tryptase for mastocytosis or anaphylaxis
• thyroid function tests

Treatment and home care

• Avoid your triggers: alcohol, hot drinks, spicy food, overheating.
• Keep cool: layer clothing, use a fan, and drink cold water at the start of a flush.
• Review medicines with your doctor. A dose change or switch often helps.
• Rosacea: sun protection, gentle skin care and prescription creams or gels. Brimonidine or oxymetazoline gels reduce redness for several hours.
• Menopause: hormone therapy is the most effective treatment for hot flashes. Non-hormonal options exist for people who cannot take it.
• Blushing from social anxiety: cognitive behavioral therapy helps. Beta-blockers are sometimes used.

Frequently asked questions

What does flushing mean medically?

Medically, flushing means a temporary reddening and warming of the skin, usually on the face, neck and chest, caused by widening of small blood vessels. It describes a symptom, not a disease, and can be triggered by emotions, heat, food, alcohol, hormones, medicines or, rarely, illness.

What does a flushing sensation feel like?

Most people feel a wave of heat that rises up the chest, neck and face, often within seconds. The skin looks pink or red and may tingle or burn. Some people sweat or feel their heart pounding. It usually fades within minutes.

What does flushing as a side effect mean?

It means a medicine is widening your blood vessels and causing temporary redness and warmth. Niacin, nitrates, calcium channel blockers, erectile dysfunction drugs, opioids and some injections commonly do this. It is usually harmless, but report it if it comes with breathing difficulty, rash or faintness.

When should I worry about flushing?

Worry if flushing comes with trouble breathing, swelling of the face or throat, or faintness, which can be anaphylaxis. See a doctor if flushing is frequent without an obvious trigger, or comes with diarrhea, wheezing, palpitations, headaches or weight loss.

Is flushing a sign of high blood pressure?

Not usually. Facial redness is common in people with high blood pressure, but it is not a reliable sign, and most people with high blood pressure have no symptoms. Some blood pressure medicines can cause flushing, so mention it to your doctor.