Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Acne

Symptoms

Acne can cause:

• Blackheads and whiteheads (comedones) – Comedones are enlarged hair follicles filled with sebum. Blackheads are comedones that have opened to the skin's surface. The color of the sebum makes them appear black. Whiteheads are comedones that are closed on the surface.

• Pimples (pustules) – These are inflamed hair follicles. The bacteria in the follicle multiply, attracting infection-fighting cells, which release substances that cause irritation and redness. The follicle then ruptures and spills the contents into the surrounding skin, which causes more inflammation.

• Nodules and cysts – These are larger infections of the hair follicles that extend deeper into the skin, forming firm, deep bumps and swellings. Like pimples, they are caused by increased sebum production and the growth of bacteria, which cause irritation and redness.

In girls and women, acne often flares up at certain points in the menstrual cycle.

Acne can cause:

• Blackheads and whiteheads (comedones) – Comedones are enlarged hair follicles filled with sebum. Blackheads are comedones that have opened to the skin's surface. The color of the sebum makes them appear black. Whiteheads are comedones that are closed on the surface.

• Pimples (pustules) – These are inflamed hair follicles. The bacteria in the follicle multiply, attracting infection-fighting cells, which release substances that cause irritation and redness. The follicle then ruptures and spills the contents into the surrounding skin, which causes more inflammation.

• Nodules and cysts – These are larger infections of the hair follicles that extend deeper into the skin, forming firm, deep bumps and swellings. Like pimples, they are caused by increased sebum production and the growth of bacteria, which cause irritation and redness.

In girls and women, acne often flares up at certain points in the menstrual cycle.