Blackhead or open comedone: what is it?

Also called an open comedo, the blackhead is a retention lesion that represents the first stage of acne. This skin imperfection results from a biological dysfunction within the pilosebaceous follicle. It all starts with hyperseborrhea, meaning an excessive production of sebum, combined with hyperkeratinization. The latter refers to an abnormal buildup of dead cells on the skin’s surface. This dense mixture ultimately blocks the pore and creates a plug, more precisely a comedo.

When exposed to air, the lipids contained in this plug oxidize, turning the tip of the comedo into a small, hard black bump on the surface of the skin.

This type of blackhead is observed mainly in areas that are rich in sebaceous glands. The face is the most exposed area, with a high concentration on the T-zone, often leading to the formation of blackheads on the nose or comedones on the nose. However, other more unexpected areas can also be affected: it is not uncommon to see a blackhead in the ear or a black spot on the ear, where the skin is also thin and prone to secretions. Likewise, the perioral regions are susceptible to these blemishes. One may therefore notice blackheads around the mouth, blackheads around the lips, or even exactly on the lip border.

If left untreated, these comedones can progress in two ways. They may rupture and release their contents under the pressure of a comedone extractor or the fingers, with a risk of scarring. More problematically, the blackhead can become inflamed through the action of bacteria such as Cutibacterium acnes, thereby progressing to an inflammatory stage.

Although the formation of a blackhead is a natural physiological process, several internal and external factors can accelerate pore blockage and increase the number of blackheads. Here are the main ones:

• Hormonal fluctuations : Androgen hormones play a major role in activating the sebaceous glands. During puberty, pregnancy, menstrual cycles, or after stopping a birth control pill, sebum production tends to increase. This hormone-induced hyperseborrhea often explains why open comedones appear in a cyclical pattern.

• The nature of the skin : Combination to oily skin types are inherently more prone to retentional acne. By nature, these skin types have more active sebaceous glands and more dilated pores, which facilitates the clumping of corneocytes. This explains the recurrence of comedones on the nose, or blackheads on the nose, where the density of glands is highest.

• The use of unsuitable cosmetics : Applying so‑called “comedogenic” products can create an occlusive film that prevents the natural flow of sebum and promotes the formation of blackheads.

• Environmental factors : Pollution and exposure to UV radiation also contribute to the oxidation of squalene, a component of sebum, making it more viscous and darker, which promotes the formation of blackheads.

Even if it is tempting, it is better to avoid eliminating a blackhead by extracting it manually.

Squeezing a blackhead with your fingers—whether it’s a blackhead on the nose or one on the ear—can damage the surrounding tissue, spread bacteria, and turn a simple retention lesion into an inflammatory pimple. While using a comedone extractor can be considered occasionally and under sterile conditions, the most effective strategy remains the use of keratolytic active ingredients. Salicylic acid is the reference ingredient here: by penetrating into the pore, it dissolves the plug of sebum and dead cells, making it easier to clear the open comedone without irritating the skin.

Cleansing is the other fundamental pillar for preventing and reducing blackheads. A double cleanse in the evening, starting with a cleansing oil, dissolves lipid-based substances by affinity, such as sebum, sunscreen filters, and makeup, before continuing with a water-based cleanser. By clearing the opening of the pilo‑sebaceous canal every day, this limits lipid oxidation and the formation of new blackheads.

Finally, a complete skincare routine should be followed with a moisturizing cream and a sunscreen in the morning. Contrary to some common beliefs, skin that is prone to blackheads should not be dried out, as this may trigger a defensive overproduction of sebum, a phenomenon known as reactive hyperseborrhea. In addition, using a purifying mask once or twice a week, for example one based on clay, can help absorb excess oil and prevent blackheads.

In cases of numerous, recurrent, or distressing blackheads, it is also possible to turn to aesthetic medicine solutions, such as laser treatments or chemical peels.

• MILLS O. & al. Microbiology of comedones in acne vulgaris. Journal of Investigative Dermatology (1973).

• WU I-T. & al. Clinical evaluation of salicylic acid scrub, toner and mask in reducing blackheads. Journal of the American Academy of Dermatology (2004).

• JIN C. & al. Effectiveness of the optimal pulse technology in a novel technique for treating nasal blackheads in Asians: A clinical study. Journal of Cosmetic Dermatology (2025).