Why does it occur
Acne occurs when glands (called sebaceous glands) in the follicles of the skin become overactive. These glands produce sebum, an oily substance that helps to stop the skin drying out. Someone with acne produces too much sebum, which forms a plug with dead skin cells and blocks the follicle.
If the blocked follicle is close to the skin surface, it balloons outwards and forms a whitehead. If the plug it the top of the follicle – opening on to the skin surface, it can be seen as a blackhead.
Bacteria that live on the skin – and which are usually completely harmless – can then infect the plugged follicles. This can cause the surrounding skin to become red and sore, and produce pus, leading to spots, nodules and cysts.
Areas of skin with the most follicles are the face, upper back and chest, which explains why acne tends to occur in these regions.
Why do some people have acne but not others?
The exact cause of acne is not known, but it is probably associated with several related factors:
Teenagers are particularly prone to acne because levels of hormones (known as androgens) increase at puberty. These hormones cause an increase in the size of the sebaceous glands and the amount of oil they produce.
Hormonal changes occurring in pregnancy, or on starting or stopping birth control pills (the Pill) can also cause acne.
Acne can also run in families. If one or both or your parents had acne, or a brother or sister, this can increase your chances of developing the condition.
Certain medicines, including androgen hormones, and lithium, can cause acne.
Why does acne sometimes get worse?
Several factors can cause acne to get worse:
- Changing levels of hormones in teenage girls and women, usually two to seven days before their period starts.
- Oil from skin products, such as moisturisers and make-up, or grease in the workplace (such as a kitchen with fryers).
- Irritants in the environment, such as air pollution or humid conditions
- Squeezing or picking blackheads, whiteheads or spots
- Scrubbing the skin
Why is acne worth treating?
Most people find even mild acne distressing, and want to get rid of it. People with severe acne may develop permanent scarring, so it is important to see your doctor to reduce this risk.
The good news is that there is a range of effective treatments available, which can prevent new spots and reduce the risk of scarring.