Acne usually starts during puberty and stops around five years later in seven out of 10 people. It's much less common in later life. Occasionally, newborn babies can get acne in the first few weeks or months of life.
Acne starts to develop when hair follicles in your skin become blocked with the natural oil produced by your skin (known as sebum) and dead skin cells. Each follicle is connected to a sebaceous gland that lies just underneath the surface of your skin. The sebaceous glands produce sebum to keep your skin soft and supple. Normally, sebum travels up the follicle and out through small holes (pores) on the surface of your skin. However, if your body produces too much sebum, and dead skin cells get trapped in your pores, a 'spot' will form. This can either be a whitehead or a blackhead.
Sometimes the bacterium Propionibacterium acnes, which normally lives on the surface of your skin, causes inflammation (but not infection) in your hair follicles. If the inflammation develops near the surface of your skin, red or yellow spots (pustules) can form. Deeper, inflamed lesions (nodules and cysts) can form if the inflammation is nearer the hair root. In very severe acne, cysts may join together to form even larger, deeper inflamed lesions (acne conglobata), but this is rare.
Acne isn't infectious, so you can't catch it or pass it on to other people.
If you have mild or moderate acne, you may have greasy skin and spots (whiteheads or blackheads) on your face, back and chest. Most spots will not cause any other symptoms. Sometimes, spots that have become inflamed (pustules, nodules and cysts) may be painful, tender to touch and your affected skin may feel hot.
Most people have a mild form of acne that usually clears up after their teenage years, but sometimes more severe complications may develop if you have moderate or severe acne.
Contrary to popular belief, acne isn't caused by poor diet or bad hygiene.
During puberty, both men and women produce more of the male hormone testosterone. This increases the production of sebum in your skin, causing it to become greasy and encouraging spots to form. It's thought that this is one of the main reasons most teenagers develop acne during puberty. If you have acne, it doesn't necessarily mean that you have abnormally high levels of testosterone. It’s more likely that you have normal levels but that you’re more sensitive to its effects.
If you're a woman, hormonal changes during your menstrual cycle and pregnancy may trigger acne.
Acne can be hereditary. For example, if both your parents had acne you have an increased chance of having it too.
Other less common causes of acne may include:
Acne can usually be treated with over-the-counter creams and lotions. However, if your acne doesn't improve with self-help measures, or is affecting you emotionally, see your GP. If you’re uncertain whether or not you have acne, then speak to your pharmacist. Acne is easily recognisable by the distribution of spots on your body. Depending on how severe your acne is, your pharmacist or GP will recommend the most appropriate treatment.
There are many different types of treatment for acne.
By keeping your skin clean you can help to prevent spots forming. Gently wash spot-prone areas with a mild soap or an unperfumed cleanser in lukewarm water about twice a day. Try not to wash the affected areas more than this, or scrub too hard, as your skin needs a certain amount of oil to maintain its natural condition. Acne isn't an infection, so extra washing won't help. Take care not to scrub or pick acne, as this can make it worse, and make sure you remove all of your make-up at night. If your skin is dry (some acne creams can cause dry skin) you can use a fragrance-free, water-based emollient.
You may also be able to try an over-the-counter treatment that contains benzoyl peroxide (eg Oxy, Clearasil) – this has an antibacterial action and encourages your skin to shed its surface layer of dead cells. Together, these effects reduce the inflammation in existing spots and prevent new ones forming. You can buy these treatments from pharmacies and larger supermarkets.
Treatments containing benzoyl peroxide may cause your skin to become irritated (slightly reddened), especially to start with. This tends to settle down if you reduce the number of times you use it. You can then build up your use gradually.
Self-help treatments for acne take time to improve your skin noticeably, so it's important not to expect a big difference overnight. Your acne may only get better several months after you have been using the treatment regularly.
If your acne hasn't improved with self-help measures after about two months, see your GP. He or she may prescribe one of the following treatments.
If you have moderate acne, your GP may prescribe an antibiotic such as oxytetracycline, erythromycin or doxycycline. He or she will advise you how many times a day you need to take your medicine, but you will need to stay on the course for a minimum of eight weeks. You may find it takes up to six months for your skin to improve and if your acne is severe, you may need to continue treatment for longer. You may also need to apply a cream or lotion containing benzoyl peroxide to increase the effectiveness of your antibiotic treatment.
If you're a woman and treatments with oral antibiotics haven't worked, your GP may advise taking an oral contraceptive pill, such as cyproterone acetate (eg Dianette). These medicines suppress the male hormones which are responsible for increasing sebum production and help make your skin less oily. You may find it takes up to three months for your skin to improve when you first start taking oral contraceptives. Generally, you will be given these together with other treatments to treat acne.
If you have severe acne, or acne that has proven resistant to other treatments, your GP may refer you to a dermatologist (a doctor specialising in skin conditions) for treatment with an oral retinoid (eg isotretinoin). These medicines are very effective at reducing the amount of sebum your skin produces.
If you're a woman, you should try to use two effective forms of contraception for at least one month before treatment, as well as during treatment, and for at least one month after stopping. This is because oral retinoids are teratogenic and could affect the development of an unborn baby. So for safety reasons, you will be asked to take regular pregnancy tests and will be limited to one month's supply of the medicine.
Oral retinoids usually cause dryness of your lips and occasionally nose bleeds and muscle pains. They are associated with a number of possible side-effects including low mood. If you have ever had low mood or depression in the past, you must let your dermatologist know before you start treatment. It's also recommended that you keep your alcohol intake to a minimum when you're being treated with isotretinoin.
You will have the opportunity to fully discuss all of these issues and ask any questions you may have with your dermatologist before you start treatment.
Light treatment is sometimes used to treat acne. Lights work by targeting the P. acnes in the sebaceous glands. Laser treatment may also be used to help with scarring caused by acne. For more information, speak with your dermatologist.
Produced by Rebecca Canvin, Bupa Health Information Team, January 2013.