Why does rosacea occur?

por que aparece la rosacea

You may have been dealing with redness on your face for some time. Maybe you’ve also been dealing with pimples that come and go. If you’ve already been diagnosed, you’re probably wondering why rosacea occurs and what things you can do to make it less of a nuisance.

Rosacea, which affects up to 3% of the population, is a chronic disease that is highly prevalent in adults. It is more common in women and usually (but not always) fair-skinned. It can manifest itself in different ways combining redness, burning and pimples especially, which you can read about in my article “the two faces of rosacea” (in Spanish)

In this article I will review the different factors involved in the development of rosacea according to the most up-to-date scientific evidence.


A large proportion of people with rosacea feel their skin redder than normal, either constantly or in flare-ups. Many times this redness is accentuated by temperature changes, physical exercise, alcohol or spicy food.

The variations in the pink color of our face depend on the amount of blood circulating in the superficial part of the skin. Thus, the more dilated the blood vessels of the skin are, the more blood will circulate through them. Thus, the redness of the face will be more evident. The same is true if he number of vessels increases, which is a common occurrence in rosacea.

Neurovascular dysregulation is believed to be one of the most influential factors in the origin of rosacea. This means that the greater or lesser opening of the blood vessels of the face is not adequate and is exaggerated in many cases. It has been found that some cell receptors (e.g. TRPV) involved in blood vessel dilation are present in greater numbers and are more active in rosacea skin than in healthy skin.


Our immune system, the one that defends us from external aggressions, is also found in the skin. There it defends us against infections caused by germs that can enter through a small wound. The defense against aggressions takes the form of inflammation, which is a natural mechanism of the body.

However, sometimes the components of this immune system can be activated in a disproportionate or inappropriate way, generating inflammatory symptoms. In rosacea we see this as increased skin sensitivity, with burning or heat in many cases.

The skin has receptors in its cells that activate the inflammatory cascade. Some of them are more numerous than normal in rosacea skin, such as the Toll-like receptor (TLR2).

On the other hand, the epidermis has the capacity to produce antimicrobial peptides naturally. It has been shown that in rosacea the production of these peptides is increased (especially CAMP and KLK5).

Similarly, certain receptors (NLRP3) that activate inflammasome in response to cell damage have been found to be elevated in rosacea skin.

Together, all these pathologically overexpressed elements induce the formation of reactive oxygen species (ROS). These trigger the release of other inflammatory molecules that in addition to maintaining inflammation contribute to increased blood vessel formation. All of this comes full circle and ties in with what was discussed in the previous section.

Why does rosacea occur? EXTERNAL FACTORS

So far we have discussed aspects that are behind rosacea from a cellular and molecular perspective. This information has been scientifically proven but is not very “palpable” in real life.

In this section, however, we will address the factors that influence from the outside that all of the above mechanisms are activated.


When wondering why rosacea appears, you may have thought about your family. You may wonder if it is related to that uncle who suffers from it or if you can pass it on to your children. Well, up to 40% of people who have rosacea have a family member with rosacea. It also frequently occurs simultaneously in twins.

However, this does not mean that your offspring will inevitably have the same condition as you. It is simply more likely.


  • Demodex folliculorum:

This is a mite that lives on our skin normally, specifically in the pores of the face. Although we all have them, people with rosacea have a greater number. In these cases (as opposed to when there are few mites in the pore), demodex has the ability to activate some of the receptors. One of them is TLR2, discussed above, which promotes inflammation.

I tell you more about this mite in my article “Demodex and rosacea: cause or consequence?” (in Spanish).

  • Helicobacter pylori:

A high percentage of us, up to 50% may have this battery in the stomach. It has been seen that this is more frequent in people with rosacea. Some types of helicobacter pylori (HP) can generate a chronic inflammation that could also influence the rosacea picture.

For all these reasons, a relationship between HP infection and the course of rosacea has been sought. It seems that the treatment to eradicate the bacteria has managed to improve the facial picture in some studies. However, this has not been the case in others. Moreover, the question remains as to whether the improvement in the first cases was due to the elimination of the bacteria or to having taken antibiotics.

Therefore, their relationship is still controversial.


Dermatologists always advise you to use sun protection if you suffer from rosacea because it is well known that the sun in general is not beneficial for this condition. The effect of ultraviolet radiation on rosacea is mainly due to its ability to induce the formation of ROS.

ROS are chemical compounds that can damage skin molecules directly. As such, people with rosacea have higher levels of ROS than people without rosacea. These ROS are thought to help propagate the inflammatory cascade explained above. In addition, they have the ability to damage collagen and elastin in the dermis, both proteins that help support the skin.

To sum up…

There is no single, precise answer to the question of why rosacea appears. A number of factors, both external and internal, can lead to the appearance of outbreaks. It is likely that in some people some of them have more weight than others. It is important to be evaluated by a dermatologist in person or online dermatologist to establish and optimize the best treatment according to the particular characteristics of your rosacea.

If you have come here wondering why rosacea appears, has this article helped you?

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