Introduction

If you have acne, it means you get spots. Lots of us have acne when we're teenagers. But it can affect older people too. Acne may appear briefly or last for many years. Very severe acne sometimes causes scarring, but treatment can help prevent this.

We've brought together the best research about acne and weighed up the evidence about how to treat it. You can use our information to talk to your doctor and decide which treatments are best for you.

Acne is just another word for spots. If you have severe acne, you get lots of spots, or spots that are large, red, and sore.

Most people don't like it when they get spots on their face. Acne can also affect other parts of your body. You can get it on your neck, chest, back, and arms.

Spots happen when you get a build-up of natural oil under your skin. Small glands in your skin make an oily substance called sebum. This stops your skin drying out.

Sebum comes out onto the surface of your skin through tiny holes called pores.

If a pore becomes blocked, sebum can build up. This can cause several kinds of swellings or spots on your skin.

• If sebum builds up just under your skin, you get white bumps called whiteheads.

• Blocked pores can get quite wide and open up. This causes small dark marks called blackheads. The black bit is a plug of oily sebum and protein from your skin. It's not dirt.

• Spots can turn red and become inflamed. These are called papules. They happen if bacteria start growing in the sebum that's built up.

• Some inflamed spots contain pus. These are called pustules.

Spots can go deep in your skin and become painful.^[1] Very bad spots can cause scars as they heal.^[2]

You may hear spots called pimples or zits.

What causes acne?

We don't know exactly what causes acne.

The main reason teenagers get acne is probably the change in hormones that happens when you reach puberty.^[3] The change in hormones can cause your skin to make more sebum (oil). The extra sebum can make your skin greasy.

You're more likely to have acne if other people in your family have it.^[4] And some kinds of oily make-up may block your pores and trigger acne.^[4]

If you have acne, there are things that can make it worse:^[4]

• Rubbing your skin

• Picking or squeezing your spots

• Tight clothes or bag straps that rub your skin

• Pollution and high humidity

• If you're female, the change in your hormones that happens when you have your periods, or when you start or stop taking the contraceptive pill.