What Causes Blackheads and Whiteheads to Form? Understanding the Origins of Comedones

What Causes Blackheads and Whiteheads to Form? Understanding the Origins of Comedones

Blackheads and whiteheads, collectively known as comedones, are among the most common forms of acne. Though they might seem simple, their formation involves a complex interplay of skin biology, oil production, and external factors. Understanding how these tiny bumps develop can help you take preventive steps and choose effective treatments to keep your skin clearer.

The basics: how comedones start

The skin on our face contains numerous tiny openings called pores. Each pore houses a hair follicle and sebaceous gland, which produces sebum — the natural oil that keeps skin soft and hydrated. Problems begin when this process becomes unbalanced.

Here’s a step-by-step look at what happens:

1. Excess oil production: Hormonal changes, genetics, or other triggers can lead to the sebaceous glands producing more sebum than usual.

2. Abnormal shedding of skin cells: Normally, dead skin cells rise to the surface and are shed naturally. In acne-prone skin, these cells stick together and mix with excess oil.

3. Clogged pores: The sticky blend of oil and dead cells becomes trapped within the pore, creating a “plug” that blocks the pore opening.

This plug is what we call a comedo (plural: comedones). Depending on whether the pore remains open or closed, it becomes either a blackhead or a whitehead.

Blackheads vs. whiteheads: what’s the difference?

• Blackheads (open comedones):
  In blackheads, the pore remains slightly open. The surface of the plug is exposed to air, and the melanin (a natural pigment in our skin) within the trapped oil oxidizes, turning it black or dark brown. This isn’t dirt — it’s simply the chemical reaction of melanin with oxygen.

• Whiteheads (closed comedones):
  In whiteheads, the clogged pore remains closed under a thin layer of skin. The plug is not exposed to air, so it appears as a small, flesh-colored or white bump.

What triggers blackheads and whiteheads?

Several factors can increase the risk of comedone formation:

✅ Hormonal changes: Androgens, the hormones that increase during puberty, menstruation, and sometimes pregnancy, stimulate sebaceous glands to produce more oil.

✅ Genetics: If your parents had acne or oily skin, you’re more likely to develop blackheads and whiteheads.

✅ Skincare and cosmetic products: Using products with comedogenic (pore-clogging) ingredients can worsen clogged pores.

✅ Sweat and humidity: Hot, humid weather or heavy sweating can contribute to clogged pores, especially if sweat mixes with oil and dead skin.

✅ Diet and lifestyle: While research is ongoing, some evidence suggests that high-glycemic foods and dairy may trigger acne in certain people.

✅ Improper cleansing: Not washing your face regularly — or washing too aggressively — can disrupt the skin’s oil balance and worsen blockages.

Can bacteria cause blackheads and whiteheads?

Bacteria play a bigger role in inflamed acne (like pimples and cysts). While blackheads and whiteheads themselves aren’t directly caused by bacteria, clogged pores can create an environment where bacteria thrive, leading to inflamed acne if untreated.

Final thoughts

Blackheads and whiteheads form when excess oil, dead skin cells, and other debris clog pores. The difference lies in whether the pore stays open (blackhead) or closed (whitehead). Good skincare habits, gentle cleansing, and non-comedogenic products can help keep comedones under control. If clogged pores persist, a dermatologist can recommend treatments tailored to your skin type, including topical retinoids, exfoliants, or professional extractions for clearer skin.