What causes an open comedo and an open comedo?

Comedones , commonly known as blackheads and whiteheads , are types of skin imperfections that result from blocked pores. Understanding what causes a closed comedo (whitehead) and an open comedo (blackhead) is essential to adopting effective prevention and treatment strategies.

What are comedones?

Comedones form when skin pores become clogged with a combination of sebaceous material , dead skin cells, and sometimes bacteria. Comedones can be classified into two main categories: closed comedones and open comedones.

What is a closed comedo, also called a whitehead?

A closed comedo , also called a whitehead , forms when the blocked pore remains closed on the surface of the skin. This creates a small white or flesh-colored bump.

Here are the main causes of the formation of a closed comedo:

  1. Excess sebum : The sebaceous glands produce an excessive amount of sebum, an oily substance intended to lubricate and protect the skin. This excess sebum can clog pores.
  2. Accumulation of dead cells : Dead skin cells are not eliminated effectively, they can mix with sebum and clog pores.
  3. Bacterial overgrowth : Bacteria can multiply inside clogged pores, causing inflammation.
  4. Comedogenic cosmetic products : Some skin care and makeup products can clog pores, encouraging the formation of closed comedones.

What is an open comedo, also called a blackhead?

An open comedo , or blackhead , forms when the blocked pore remains open on the surface of the skin. Air oxidizes the sebaceous material, giving it a black color. The causes of an open comedo are similar to those of a closed comedo:

  1. Excess sebum : As with closed comedones, excessive sebum production by the sebaceous glands can clog pores.
  2. Accumulation of dead cells : Dead skin cells mix with sebum and clog pores.
  3. Oxidation : When the blocked pore remains open, the sebaceous material inside the pore oxidizes on contact with air, turning black.
  4. Pollution and impurities : Environmental impurities can accumulate in open pores, contributing to the formation of blackheads.

How to prevent blackheads from appearing

The essential step to prevent the appearance of blackheads is cleansing morning and evening with a suitable treatment based on ingredients such as salicylic acid and probiotics . The essential rule to prevent blackheads is to maintain good skin hygiene. Effective skin cleansing removes excess oil, as well as dead cells and impurities that can clog pores. However, it is crucial to adopt a gentle and skin-friendly routine to avoid negative effects. Indeed, products that are too aggressive can irritate the epidermis, leading to overproduction of sebum and thus increasing the risk of blackheads.

Here are some recommendations for an optimal care routine:

  • Cleanse your skin morning and evening with a gentle product.
  • In the evening, remove makeup from your skin before cleansing it.
  • Always moisturize your skin after each cleansing, whatever your skin type. Contrary to popular belief, oily skin also needs hydration (read: “Which moisturizer for oily skin?”).

To limit the overproduction of sebum, follow these tips:

  • Limit UV exposure as much as possible. Whether in the sun or in the cabin, UV rays promote thickening of the skin, which hinders the flow of sebum.
  • Use high protection sunscreen when outdoors.
  • Opt for non-comedogenic products adapted to your skin type, whether skincare products, sunscreens or cosmetics.
  • Avoid overloading your skin with too much makeup.
  • Eat a balanced diet rich in vegetables. Reduce the consumption of fatty, sugary, ultra-processed foods and stimulants like coffee.
  • If you notice excess oil production after taking certain medications, consult your doctor to discuss possible side effects.
  • In cases of acne, whether microcystic or not, drug treatment may be necessary to reduce comedones. Consult a dermatologist for appropriate treatment.

By following these tips, you can effectively reduce the appearance of blackheads and maintain healthy, balanced skin.

How to get rid of blackheads?

To get rid of blackheads effectively, it is crucial to adopt a comprehensive and targeted approach. Comedones, whether open or closed, are often the result of the buildup of dead skin cells, excess oil, and sometimes even bacteria in the pores. To counter these factors, it is recommended to use treatments specifically formulated to act on their origin .

Salicylic acid is one of the most effective ingredients for treating blackheads. By deeply exfoliating pores, it removes dead skin cells and regulates sebum production, helping to prevent clogged pores. Retinoids are also valuable allies in the fight against blackheads. By promoting cell renewal, they help maintain the clarity of pores and prevent them from becoming clogged.

In some cases, the use of a blackhead remover may be considered to manually extract the blackheads. However, it is imperative to do this carefully to avoid scarring and infection. It is recommended to properly disinfect the skin and use gentle techniques to avoid irritation.

Finally, in the event of persistent or severe blackheads, it is strongly recommended to consult a dermatologist . These healthcare professionals have the knowledge and resources to assess your skin and recommend appropriate treatments. They may prescribe stronger topical medications, such as stronger retinoids or products containing salicylic acid in higher concentrations. In some cases, in-office procedures, such as chemical peels or professional extractions, may also be recommended to effectively remove blackheads.

In summary, by combining good skin hygiene with the use of specific treatments and possibly the help of a health professional, it is entirely possible to get rid of blackheads and obtain healthier, more brilliant.


Closed comedones (whiteheads) and open comedones (blackheads) are results of pore blockages caused by excess oil , dead cells , and sometimes bacteria. By adopting a suitable skin care routine and using the right products, it is possible to prevent and effectively treat these skin imperfections. The key is to maintain clean, well-hydrated skin while avoiding products that can clog pores.