What is acne (acne vulgaris)?
Acne (Acne Vulgaris) is a common condition which causes spots or pimples to appear on the skin. They occur when the skin’s natural oil, sebum, blocks the skin’s pores – tiny holes out of which hairs grow. The spots usually occur on the face and neck, and sometimes on the back or chest.
There are different types of spots caused by acne. Blackheads and whiteheads (which are collectively known as comedones) are small bumps over clogged skin pores that are either black/dark (blackheads) or white (whiteheads). Papules are small red pimples and, along with blackheads and whiteheads, are seen in mild-moderate acne. In moderate-severe acne, pus can build up beneath spots causing pustules. In more severe acne, the pustules can enlarge into hard nodules or pus-filled cysts.
While acne is often associated with hormonal changes during teenage years, people can get acne at any age and some may get it for the first time in adulthood. Most people experience acne at some point in their lives. Some people have just a few spots, while others have more widespread acne. About 20% of young people experience moderate-severe acne.
The main cause of acne is over-production of oil (sebum) by sebaceous glands, which lie under the surface of the skin.
How are spots formed?
Normally, sebum is secreted by the glands onto the skin via tiny holes known as pores or follicles. Hairs also emerge out of these pores/ follicles. In acne, too much sebum is produced, which can cause the pores to clog up.
Dead skin cells from the outermost surface of the skin are also shed into the pores, mixing with the sebum. This forms a plug that blocks the pore. When this occurs, comedones (blackheads and whiteheads) are formed.
Blackheads form when the sebum plug is open to the skin (open comedo) and in contact with the outside air. This causes a skin pigment that is present in the sebum (melanin) to react with oxygen, turning it dark or black in colour.
Whiteheads form when the sebum plug is closed to the surface skin (closed comedo) and not in contact with the air.
Sebum can also collect underneath the blocked pore, causing pimples or “papules”. Bacteria that usually live harmlessly on the skin (Propionibacterium acnes) reproduce more aggressively in the oily environment of the blocked pore, and can produce pus and cause inflammation. When this happens, pus-filled spots known as “pustules” develop. In more severe acne, the pustules can enlarge into nodules of cysts.
What causes over-production of sebum?
Sebum production is affected by changes in hormone levels, which is why acne is more common in teenagers going through puberty. Other factors that affect hormones, such as the contraceptive pill and pregnancy, can also cause acne.
Hormonal changes may also thicken the cells lining the pores, making them more likely to clog up with dead skin cells and oil.
Some medications, including steroids, lithium and certain anti-epileptic drugs, may also cause acne.
Acne often happens with no obvious cause. There are some myths about acne that are worth debunking:
- It’s not caused by poor personal hygiene or dirty skin
- It doesn’t mean you have a poor diet
- It’s not infectious – you can’t catch acne from someone else.
The typical symptoms of acne are oily skin, comedones (blackheads and whiteheads), papules (pimples) and pustules (small pus-filled swellings). Most people have a combination of these, although not everyone gets pustules. Areas of skin affected by acne may feel hot, sore or itchy.
Types of spots in acne
Comedones are small swellings caused by oil and dead skin plugging the pores of the skin. Blackheads have a dark appearance, caused by skin pigmentation (not by dirt). Whiteheads tend to be just below the surface of the skin, are unpigmented and appear as small white dots.
Pustules are spots with a build-up of pus beneath them. They can be red or yellow, with a white tip. They happen when normal skin bacteria grow in the oil and dead skin build-up of a comedone.
More severe acne can cause infected pustules, called cysts. Cycsts are large pus-filled lumps. Sometimes these burst, releasing pus. Cysts may need treatment, to avoid the chance of them causing scars.
Severe acne can also cause nodules – large, hard lumps under the skin. They are caused by inflammation in blocked follicles and may be painful.
Most people with acne get it on the face or neck. About 50% of people have acne on their back, and about 15% of people develop on their chest. Some people with more severe acne are left with scars from pustules and cysts.
Many people find acne embarrassing. It can trigger self-consciousness, loss of confidence and social anxiety.
People don’t usually need any tests for acne. A doctor can diagnose acne by looking at the type of spots and where they are on the body. There are four different grades of acne: mild (grade 1), moderate (grade 2), moderately severe (grade 3) and severe (grade 4). A doctor may use these to plan appropriate treatment.
Treatments range from self-help measures to prescription-only medicines, depending on how severe the acne symptoms, and how much they bother you. The aim is to reduce the appearance of spots, and to avoid scarring.
Treatment options include:
Benzyl peroxide creams and gels
Over-the-counter gels and creams that contain the antiseptic benzyl peroxide are usually the first option to try for acne. They are widely available from pharmacies. The gels/creams should be used once or twice a day, for about six weeks. Benzyl peroxide works by reducing the amount of Propionibacterium acnes bacteria on the skin. It may also reduce the production of sebum.
Benzyl peroxide gels and creams may sting, and should be used sparingly. They may also cause the skin to become sensitive to UV light, so your doctor may advise you to wear sun cream and limit your exposure to sunlight.
Retinoids, which includes drugs such as tretinoin and adapalene, are substances that are similar in chemical structure to Vitamin A. Retinoid gels and creams are prescribed for acne because they can help unblock clogged pores. They may also reduce inflammation. Studies show topical retinoids to be effective in reducing blackheads, whiteheads and mildly inflamed spots.
Retinoid gels and creams are usually used once a day, before bed. They shouldn’t be used during pregnancy, and you should avoid sun exposure after use of retinoid creams. They may sting or cause redness or flaky skin, and should be used as directed.
Antibiotic lotions or gels are applied to the skin once or twice daily, to reduce the amount of bacteria on the skin. They are not usually used for more than six to eight weeks, as bacteria may become resistant to them. Tetracycline, erythromycin and clindamycin are the most common antibiotics used.
In order to help unblock pores, your GP may prescribe benzyl peroxide or a retinoid cream in addition to a topical antibiotic.
Azaleic acid is an alternative if other topical treatments are too irritating or painful. It removes dead skin and reduces bacteria. You usually need to use this for four weeks before you notice an improvement.
Studies show that azaleic acid is not as effective at treating acne compared to other topical treatments (e.g. topical antibiotics or benzyl peroxide).
Antibiotic tablets are used for more severe acne, or if topical treatments alone have not worked. The type most often used is the tetracycline class of antibiotics, which includes drugs such as doxycycline, limecycline and tetracycline. They are often prescribed alongside a topical treatment, for four to six months, depending on how well they work. Tetracycline antibiotics cannot be used in pregnancy as it can cause damage
Combined Oral contraceptive pill
The combined oral contraceptive pill (commonly known as “the pill”) may be offered as a treatment to girls or women with acne. It helps acne by controlling over-production of sebum related to hormonal changes. For example, it may be helpful in acne that becomes worse at the time of a period.
A different type of pill, called co-cyprindol (Dianette) may be given when other treatments have failed. Co-cyprindol blocks the effect of hormones called ‘androgens’, which may contribute to acne in some people. Co-cyprindol is not suitable as a long term contraceptive and is discontinued after acne has cleared up.
Isotretinoin is a retinoid (substance related to Vitamin A), but one that is taken orally rather than applied to the skin. It can be an effective treatment, reducing oil production, preventing follicles from getting clogged up, decreasing bacteria and reducing swelling. However, it can have serious side effects, including mood changes, and is only prescribed by dermatologists for people with severe acne. It can’t be used during pregnancy or breastfeeding.
Laser therapy is sometimes used to treat severe acne in a hospital setting. It works by targeting and destroying Propionibacterium acnes bacteria in the sebaceous glands. Laser therapy is also occasionally used to reduce the appearance of scars that can appear due to acne.
Surgical procedures may be required for very serious acne. Cysts and nodules that are filled with pus may have to be incised (cut) and drained. Scar tissue resulting from acne can be removed by inserting and manoeuvering a needle into the scar – a surgical technique called ‘subcision’. A plastic surgeon may also consider ‘dermabrasion’ to remove scarring from acne. This involves using special rotating tool to remove the top layers of skin.
Risk factors for developing acne include:
- Taking medication that affects the hormones, for example the contraceptive pill or certain types of steroids
- Hormonal imbalances such as polycystic ovary syndrome (PCOS)
- A family history of acne.
People with acne should wash affected areas with a mild cleanser and lukewarm water, no more than twice a day. Washing too often, using harsh soaps and hot water, can make acne worse. Squeezing or picking spots can also make them worse and may cause scarring.
Make-up may help with self-confidence. Look for oil-free products (often labelled ‘non-comedogenic’).
There’s not much evidence that diet is linked to acne, but doctors advise a balanced diet with plenty of fresh fruit and vegetables.
British Association of Dermatologists http://www.bad.org.uk/for-the-public/patient-information-leaflets
British Skin Association http://www.britishskinfoundation.org.uk/SkinInformation/AtoZofSkindisease/Acne.aspx
Acne. Patient.info. Available online at: http://patient.info/health/acne-leaflet