Pustule

Pustule — a small, inflamed skin lesion that contains visible pus, typically appearing as a red bump with a white or yellow center. In acne it develops when an inflamed follicle fills with a mixture of white blood cells, oil, and cellular debris.

Key points

• Pustules are inflammatory acne lesions that sit close to the skin's surface.
• The visible pus center is what distinguishes a pustule from a solid papule.
• They are often surrounded by a ring of redness caused by inflammation.
• The pus is largely made up of dead white blood cells responding to the follicle.
• Aggressive squeezing can spread inflammation and increase the chance of scarring or dark marks.

Frequently asked

What causes the white center of a pustule?

The white or yellow center is pus, a build-up of dead white blood cells, oil, and cellular debris that collects as the body responds to an inflamed follicle.

Are pustules a sign of infection?

Pustules reflect inflammation and can involve bacteria within the follicle, but widespread, painful, or persistent pustules should be evaluated by a healthcare professional rather than self-treated.

Related topics

• What Is a Humectant?
• What Is the Skin Barrier?

This is a foundational entry in the SYNC Skin Encyclopedia and is expanded over time. Educational information only — not medical advice.