Why does rosacea happen?

What happens inside the skin?

Inflammation is normally part of the immune system's response to injury or infection. In rosacea, that response appears to become excessive. Inflammation and disruption of the skin's protective barrier help explain redness, swelling and sensitivity. Facial blood vessels also widen more readily, increasing blood flow near the surface and causing flushing. Nerves involved in sensing heat and other stimuli appear to contribute to this unusually reactive response. These systems interact rather than behaving as separate problems.24

Why do some people get rosacea?

Rosacea can run in families, but it does not follow a simple inheritance pattern. Genetic differences affecting immune responses and protection against cell damage appear to influence risk, alongside environmental exposures. Having a relative with rosacea increases susceptibility without making the condition inevitable. Rosacea usually starts in adulthood, often after 30, but younger people can develop it. It is diagnosed more often in fair skin; redness can be harder to recognise in darker skin, so cases can be missed.25

Do mites or bacteria cause rosacea?

Demodex mites live on nearly everyone's skin and are too small to see without a powerful microscope. People with rosacea often have more of them, and that increase could provoke inflammation. Mites are one possible contributor, not a complete explanation. The stomach bacterium H. pylori has also been investigated. Treating that infection has helped rosacea in some studies but not others, so its role remains unsettled. Rosacea is not caused by poor hygiene, and you cannot catch it from another person.13

Why do heat, food and stress cause flares?

Widening blood vessels normally helps the body cool down during heat or exercise. With rosacea, facial vessels respond more easily and frequently, so even brief exposure can produce flushing. Some triggers also activate sensors in the skin that set off inflammatory signals. Common triggers include sunlight, hot or cold weather, hot drinks, spicy food, alcohol, exercise and stress. Sunlight can both damage skin cells and increase inflammation. Triggers differ between people; the common list is not a list of things everyone must avoid.356

Skincare products can be triggers too, which is awkward for a shelf full of things sold as solutions.7

What can you do about it?

A symptom diary helps identify your own triggers, without turning the entire menu into a suspect list. Record symptoms alongside food, drinks, activities, weather and skincare use, then look for repeated connections. Reduce or avoid the triggers you identify.56

• Wear sunscreen with SPF 30 or higher every day.
• Use a gentle cleanser and moisturise frequently.
• Avoid exfoliants and topical products containing alcohol.
• Do not use steroid creams to treat rosacea; they can aggravate it.

When should you see a doctor?

Arrange an appointment for recurring flushing, persistent facial colour changes, bumps or burning. Rosacea can resemble acne and dermatitis, and a clinician can often diagnose it through an examination and medical history. Rosacea is not acne and will not improve with ordinary acne treatments. There is no cure, but treatment can control symptoms. Seek urgent medical care for eye pain, blurred vision, light sensitivity, a red eye or a gritty feeling: these can signal serious inflammation of the cornea, the clear front surface of the eye.37