Pimples are quite common during adolescent years. However, some people continue to suffer from acne on their back or chest in adulthood. Wherever pimples appear, the causes are due to either an excessive sebum production or a germ proliferation in sebum. Treatment depends on which of the two processes created the acne.

Ro Young-suck, a dermatologist at Hanyang University Medical Center, says, "Three out of four adults who had facial acne during puberty are still affected by acne on their body." "Back or chest acnes are mostly purulent inflammation, making them more difficult to treat than facial acne," he added.

Medicine can also cause acne in adults. "Acne-causing medicines include steroids, oral contraceptive pills and painkillers. If one stops taking these medicines, acne disappears," says Lim Ee-seok, head of Theme Clinic.

Facial pimples can be squeezed. However, doctors advise people not to squeeze acne on the back or the chest because of differences in skin texture. Compared to facial skin, body skin is more solid and dense and has more pigment cells and collagen cells, and is thus more prone to skin discoloration. "Back or chest acne should be treated by a dermatologist," says Professor Seo Soo-hong of Korea University's Anam Hospital.