The Four Drivers of Acne

Almost all acne comes down to four processes happening together in the skin. Understanding them explains why acne behaves the way it does, and why addressing only one part rarely solves it.

One: Excess oil

Your oil glands produce sebum, an oily substance that normally keeps skin healthy. In acne prone skin, often under the influence of hormones, these glands produce more oil than the skin needs. That excess oil becomes the starting fuel for everything that follows.

Two: Skin cells that block the pore

The pore is lined with skin cells that should shed steadily. In acne, they shed unevenly and stick together, forming a plug. This mix of trapped oil and skin cells is called a microcomedone, the invisible starting point of every spot, forming long before anything becomes visible on the skin.

Three: Bacteria

A bacterium that naturally lives on everyone's skin thrives in the blocked, oily pore. As it multiplies, it contributes to the process that turns a simple blockage into an inflamed spot. It is not an infection that you have caught. It is normal skin bacteria behaving differently in an environment that allows it to flourish.

Four: Inflammation

The body's immune system responds with inflammation, producing the redness, swelling and tenderness associated with active acne. Inflammation is also responsible for much of the deeper skin damage that can lead to acne marks and permanent scarring, which is why controlling inflammation is so important.

Why understanding the four drivers matters

Because acne develops through four separate but connected processes, the most effective approaches usually target more than one of these drivers at the same time. Focusing on only one factor, such as bacteria alone, often fails to address the underlying causes of acne.

Understanding how these four drivers interact helps explain why acne requires a personalised, evidence based approach rather than relying on a single product or quick fix.

Frequently Asked Questions

Which acne driver is the most important?

All four drivers work together. This is why the most effective acne management strategies usually address several biological processes rather than focusing on only one.

Is acne bacteria an infection?

No. The bacteria involved are naturally present on healthy skin. Acne develops because these bacteria multiply inside blocked pores, not because you have caught an infection.

What is a microcomedone?

A microcomedone is the tiny plug of oil and skin cells that forms beneath the surface before a visible spot appears. It is considered the earliest stage of acne development.

Reviewed by Dr Tara Treacy, GP with a special interest in dermatology (IMC 411337).

Last reviewed: 16/07/2026.

General information only. It does not replace an individual medical assessment.