What are the causes of pore enlargement?

Depending on the secretory glands to which they are connected, we can distinguish between two types of pores, which should not be confused.

• The sebaceous pores

  As their name suggests, these pores distribute the sebum across the surface of the epidermis to moisturise the skin. They are located all over the body with a few exceptions such as the palms of the hands or the soles of the feet. They are connected to the sebaceous glands. These are generally attached to hairs (hair follicles), but there are some areas where they are not, such as on the eyelids.

• sweat pores

  These pores allow the sweat produced by the eccrine sweat glands to be expelled. They cover theentire body and are not attached to hair follicles.

Please note: on the face, the visible pores that are sometimes referred to as "dilated" are in fact the sebaceous pores, called ostium (ostia in singular) in scientific language. It is this type of pores that we will be focusing on in the remainder of this article.

Pores are dynamic structures, the size of which can fluctuate, although it is genetically determined. Thus, enlarged pores are characterised by a micro-depression on the surface of the skin of the face, giving it a "tangerine skin" appearance. According to a study, skin pores are deemed "visible" and "enlarged" when their diameter oscillates between 0.06 and 0.1 mm2.

Pores dilate for a variety of reasons. This phenomenon is usually accompanied by the appearance of blackheads.Blackheads, as well asdilated pores, are most often visible onoily skin,combination skin or onblemished skin. They primarily appear on theT-zone (forehead, nose and chin), the parts of the face where the skin is oilier.Here are the main contributing factors.

• Hyperseborrhea

  Studies have shown that there is a correlation between sebum production and pore size, meaning that the more sebum the skin produces, the larger the pores will be. Furthermore, with hyperkeratinisation (accumulation of dead cells), 'plugs' known as comedones are formed. These are then able to oxidise and form blackheads.

• Skin ageing

  This cause is less well-known, yet it holds significant importance. Let's remember that the skin is supported by a dermal network of fibrous proteins (collagen and elastin) that provide it with firmness and elasticity. As we age, the production of these proteins slows down, the skin sags and the sebaceous pores can no longer maintain their shape. They slowly succumb to gravity, stretching a little more over time.

• A hormonal imbalance (during menopause, puberty or pregnancy)

  Hormonal stimulation of the sebaceous glands can lead to the dilation of pores.

• An unhealthy lifestyle

  Tobacco use or poor nutrition can be the cause of this phenomenon.

• The sun and UV rays

  After prolonged exposure to the sun, the skin tends to thicken and easily retain sebum.

• Hereditary factors (genetic predisposition) and hair thickness

• Theuse of unsuitable skincare products such as comedogenic products and poor skin hygiene

  For instance, not removing makeup leads to the accumulation of dirt and impurities on the skin's surface.

• The gender of the individual in question

  Men's skin is generally oilier than women's because they have more sebaceous glands. Therefore, men are more prone to impurities and enlarged pores.

In order to reduce the visibility of pores, AHAs (alpha hydroxy acids) are formidable. Therefore, it is highly recommended to use an astringent care product such as a serum highly concentrated in glycolic acid, which has the power to eliminate dead skin cells and thus facilitate the return of a smoother and more unified skin. In addition to its peeling effect, this acid also has a stimulating effect on the synthesis of hyaluronic acid and cell renewal.

An alternative for sensitive skin is thelactic acid, which is gentler and less irritating than glycolic acid due to its larger size (thus it penetrates less deeply into the skin).

• CHUNG K. & al. Sebum output as a factor contributing to the size of facial pores. British Journal of Dermatology (2006).

• SEO S. J. & al. Facial pores: definition, causes, and treatment options. Dermatologic Surgery (2015).