The root causes of rosacea remain unclear, but doctors have identified several factors that appear to play a role
Rosacea does not have a single cause that doctors can point to and say "this is why you have it." Instead, the condition seems to develop when a combination of factors come together—some inherited, some environmental, and some related to how your skin and blood vessels behave. People with rosacea are born with a tendency toward the condition, but something has to trigger it to appear. That trigger varies from person to person.
What researchers do know is that rosacea involves blood vessels in your face that overreact to certain stimuli, causing flushing and redness. Your immune system also appears to be involved, responding in ways that lead to inflammation and the bumps or pustules some people develop. But why this happens in some people and not others is still being studied.
Key Takeaways
- Rosacea likely develops from a combination of genetic predisposition and environmental or lifestyle triggers, not from a single cause.
- Your blood vessels and immune system both overreact in rosacea, but the underlying reason for this overreaction is not yet fully understood.
- Common triggers include heat, spicy foods, alcohol, stress, and certain skincare products, though triggers vary widely between individuals.
- Identifying your personal triggers through observation is often more useful than trying to avoid general risk factors, since what affects one person may not affect another.
Genetics: You may inherit a tendency toward rosacea
If a parent or close relative has rosacea, your risk of developing it is higher than someone with no family history. This suggests a genetic component—meaning certain traits run in families and make some people more susceptible to the condition. However, having a relative with rosacea does not mean you will definitely develop it.
Researchers believe that what gets inherited is not rosacea itself, but rather a predisposition: a skin type or immune system tendency that makes you more likely to develop the condition if other factors are present. This is why two siblings with the same parents might have very different experiences—one develops rosacea while the other does not, even though both carry similar genetic material.
Blood vessel dysfunction: How your face responds to temperature and stimuli
In rosacea, the blood vessels in your face are unusually reactive. They dilate (widen) too easily and too much in response to triggers like heat, exercise, or emotional stress. This excessive widening causes the flushing and persistent redness that characterize the condition. Over time, repeated episodes can lead to visible blood vessels on the skin surface.
Normally, blood vessels constrict and dilate to regulate body temperature and blood flow. In people with rosacea, this system appears to be set to a hair-trigger setting. A temperature change that would barely affect someone else's skin can cause significant flushing in a person with rosacea. Researchers are still working to understand exactly why this happens at the cellular level.
Immune system involvement: Inflammation beyond normal response
Your immune system's role in rosacea is becoming clearer, though the full picture is still emerging. In people with rosacea, the immune system appears to overreact to certain stimuli, releasing inflammatory substances that cause redness, swelling, and sometimes the pustules (small bumps filled with fluid) that appear on the skin. This is not an infection—your immune system is simply responding too strongly.
Some research suggests that a protein called cathelicidin, which is part of your skin's natural defense system, may be present in higher amounts or in an abnormal form in people with rosacea. This protein can trigger inflammation when it accumulates. Additionally, certain microscopic organisms that live on everyone's skin may trigger an exaggerated immune response in people with rosacea, though this is still being investigated.
Common triggers that make rosacea worse
While triggers do not cause rosacea to develop in the first place, they do cause flare-ups in people who already have the condition. The most frequently reported triggers include heat (from hot beverages, saunas, or hot weather), spicy foods, alcohol (especially red wine and beer), emotional stress, and intense exercise. Certain skincare products, particularly those that are harsh or heavily fragranced, can also provoke a reaction.
The important thing to understand is that triggers are highly individual. One person's rosacea may flare from caffeine while another person drinks coffee without any problem. Keeping a simple log of what you eat, do, and experience on days when your skin flares can help you identify your personal triggers more reliably than following a general list. What matters is learning your own skin's patterns.
Environmental and lifestyle factors that may increase risk
Certain characteristics and habits appear more common in people with rosacea, though it is not clear whether they cause the condition or simply make it more likely to appear in people already predisposed to it. Fair skin and Celtic or Scandinavian ancestry are associated with higher rosacea rates. People who sunburn easily or have a history of significant sun exposure also report rosacea more frequently.
Lifestyle factors like chronic stress, poor sleep, and extreme temperatures (whether very hot or very cold climates) seem to play a role for some people. Hormonal changes, particularly around menopause, can trigger or worsen rosacea in women. Again, these are not causes in the sense that they create rosacea from nothing, but rather factors that may activate the condition in someone genetically predisposed to it.
What rosacea is not caused by
Rosacea is not caused by poor hygiene, alcohol consumption alone, or anything you did wrong. It is not contagious, and you cannot catch it from someone else or pass it to another person. It is also not caused by allergies, though allergic reactions can sometimes trigger flare-ups in people who already have rosacea.
The old belief that rosacea was caused by heavy drinking has been largely debunked. While alcohol can trigger flare-ups in people with rosacea, the condition develops in people who do not drink at all. Similarly, rosacea is not a sign of poor skin care or neglect—it is a medical condition with biological roots, not a result of personal habits or choices.
Frequently Asked Questions
Can stress alone cause rosacea?
Stress can trigger flare-ups in people who already have rosacea, but it does not cause the condition to develop from scratch. You need a genetic predisposition for rosacea to appear. Stress may be the factor that activates it, but without that underlying tendency, stress alone would not create rosacea.
Does rosacea run in families?
Rosacea does tend to run in families, suggesting a genetic component. If a parent or sibling has rosacea, your risk is higher than someone with no family history. However, having a family member with rosacea does not may provide you will develop it.
Can diet cause rosacea?
Diet does not cause rosacea to develop, but certain foods and beverages can trigger flare-ups in people who already have it. Spicy foods, hot drinks, and alcohol are common triggers for many people, though triggers vary individually. Identifying your personal food triggers through observation is more useful than avoiding foods generally.
Is rosacea caused by an allergy?
Rosacea is not an allergic condition, though allergic reactions can sometimes trigger flare-ups. Rosacea involves blood vessel and immune system dysfunction, not the allergic response your body has to specific substances. You can have both rosacea and allergies separately.
Why did rosacea suddenly appear when I never had it before?
Rosacea can appear at any age, even if you had no symptoms earlier in life. You may have always had the genetic predisposition, but a combination of triggers—stress, hormonal changes, sun exposure, or something else—activated it. This is why rosacea sometimes seems to appear "out of nowhere."