Sebaceous Filaments versus Blackheads: What Are the Differences?

The sebaceous filaments are natural filamentous structures in white to pale yellow that line the walls of pores of the skin. They represent a specific functional state of sebaceous follicles: their purpose is to help channel the flow of sebum from the sebaceous gland to the skin surface, where it protects the epidermis from dehydration and environmental aggressors. Sebaceous filaments are found in facial areas that produce more sebum (sides of the nose, nasolabial folds, cheeks, and forehead).

Absent in children, they appear at puberty and become more common in adulthood. Although everyone has them, people with oily skin or enlarged pores are more likely to notice them. Sebaceous filaments become visible when the pore fills with sebum and expands. Follicular filaments regenerate in three to five weeks.

Should you remove sebaceous filaments?

Though not attractive, sebaceous filaments are not considered imperfections They cause no discomfort and have no pathological significance. Thus, no reason to try to remove them manually, risking skin inflammation from pressure on the area, promoting bacterial proliferation within the weakened pore and leading to a blemish.

Moreover, even if you try to extract or squeeze your sebaceous filaments, this will lead to their rapid return within 30 days, or even sooner if you have oily skin. However, it's possible to minimize their appearance by adopting an appropriate skincare routine that aims to control sebum production and minimize pore congestion.

The blackheads, also called open comedones, result from an accumulation of sebum, keratin, and dead cells inside the hair follicle. Unlike sebaceous filaments, they form when buildup causes a partial blockage of the pore opening, stopping sebum exit. This blockage creates an environment that favors oxidation of the sebum-keratin mix on contact with air, which explains their dark hue. They are not dirt but a natural chemical reaction.

Blackheads are considered a noninflammatory form of acne.

Blackheads most often appear on the nose, forehead, chin, or back—areas with a high density of sebaceous glands. They may occur singly or in clusters. Unlike sebaceous filaments, which appear uniform in pores, blackheads are discrete, deeper, and denser. To remove blackheads, the first step is to manipulating or dislodging them with your fingers. Fingernails harbor bacteria, which can infect the skin and aggravate the condition. Instead, adopt an appropriate care routine that includes a cleansing gel and a moisturizing cream, along with exfoliating and keratolytic agents, such as glycolic acid and retinoids.

Sebaceous filaments are often mistaken for blackheads. They look identical and appear in the same areas. This confusion is common since they often coexist on combination to oily skin, especially in the T-zone. Sometimes the tip of a sebaceous filament darkens slightly due to oxidation of the fatty acids in sebum when exposed to air, resembling a blackhead. Yet this oxidation is subtler and more superficial than that in open comedones.

First, the sebaceous filament is a natural structure around hair follicles, whereas a blackhead is a skin disorder resulting from pore blockage by a cluster of oxidized sebum and dead cells. In other words, sebaceous filaments contribute to the skin’s physiological balance, while open comedones are linked to an imbalance in sebum production and the keratinization process. In addition, blackheads lie at the skin’s surface, whereas sebaceous filaments extend deeper into the skin without clogging pores. Sebaceous filaments remain aligned with the follicle walls and allow normal sebum flow to the skin’s surface.

You can also distinguish them with a simple test. When you extract a blackhead — a practice you should avoid — it appears as a dark plug. By contrast, pressing a sebaceous filament releases a thin, waxy column of sebum with a dark tip. The column is uniform and returns to its original position because sebaceous filaments recur and reform naturally. For these reasons, eliminating sebaceous filaments is unnecessary.

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

• DABBAS D. & al. Sebaceous filaments. Dermatology Practical & Conceptual (2021).

• HSU S. & al. A case report of sebaceous filaments. Cureus (2023).