Acne: causes, treatment and how long it lasts

Treatment depends on how severe the acne is. The first step, according to the British Association of Dermatologists (BAD), is skincare products suitable for blemish-prone skin, which may be labelled non-comedogenic or oil-free. Active treatments that can be bought without a prescription include benzoyl peroxide, azelaic acid and nicotinamide, and a pharmacist can advise. If over-the-counter products have not worked after a fair trial, see a GP.

NICE Clinical Knowledge Summaries describe a stepped approach for GPs. People with mild-to-moderate acne should be offered a 12-week course of a fixed combination of topical medicines applied once daily in the evening, and people with moderate-to-severe acne a 12-week course of a topical combination, or a topical treatment together with an oral antibiotic (lymecycline or doxycycline). Follow-up is arranged at 12 weeks to see whether the acne has improved.

The BAD describes acne as a very common skin condition identified by blackheads and whiteheads (comedones) and pus-filled spots (pustules). It ranges from a few spots on the face, neck, back and chest to a more severe problem with solid painful lumps under the skin, and it may cause scarring. It usually starts at puberty, although it can occasionally affect young children, and can also begin for the first time in people in their late twenties and beyond.

NICE describes acne vulgaris as a chronic inflammatory skin condition affecting mainly the face, back and chest, characterised by blockage and inflammation of the pilosebaceous unit (the hair follicle and its oil gland).

The BAD says acne is caused by a combination of factors. Oil-producing (sebaceous) glands near the surface of the skin are particularly sensitive to hormones, even at normal levels, and produce too much oil. At the same time the lining of the pores thickens and dead skin cells build up and block the pores. Harmless bacteria that live on everyone’s skin multiply in the oil and cause inflammation, producing red, swollen or pus-filled spots.

The NHS lists changes in hormone levels, such as during puberty, periods, menopause and pregnancy, conditions such as polyendocrine metabolic ovarian syndrome (PMOS, previously called PCOS) and rosacea, certain medicines, and products used on the skin or hair that make it greasy. NHS inform adds family history, wearing items that put pressure on an area of skin, such as a headband or backpack, and smoking. The BAD adds anabolic steroids and some hormonal contraceptives or high-dose steroids.

NHS inform says there is no evidence that poor hygiene or sexual activity play a role in acne. The BAD says there is not enough evidence to support specific diets for treating acne, though a healthy, well-balanced diet is advisable.

The NHS, NHS inform and NICE give consistent self-care advice. These steps will not cure acne but can stop it being made worse.

• Wash the affected skin twice a day, no more, with a gentle cleanser or mild soap and lukewarm water. NICE advises avoiding over-cleaning.

• Remove make-up at the end of the day and use skincare and make-up products that are non-comedogenic or oil-free.

• Do not pick or squeeze spots, because this can cause scars. Do not scrub the skin as this can irritate it and make acne worse.

• Wear loose, breathable clothing if you have acne on your body, especially when exercising or sweating.

• Try treatments such as salicylic acid or benzoyl peroxide, and ask a pharmacist for advice.

• Be patient: it can take several months of treatment before symptoms improve, so continue even if there is no immediate improvement.

The BAD says that, in most cases, acne goes away by the early to mid-twenties, and in other cases it can go on for longer. NHS inform says most people have acne on and off for several years before their symptoms start to improve as they get older, and that in some cases it continues into adult life. The BAD says that at present there is no cure for acne, but treatments can be very effective, preventing new spots and reducing scarring.

Treatments are slow. The BAD says most take 2 to 4 months to produce their full effect, and NICE says they may take 6 to 8 weeks to be effective and may irritate the skin, especially at the start. Isotretinoin courses last around 6 months, according to the BAD, and acne often becomes a little worse for a few weeks before it improves.

NHS inform says acne is common in women and can be a sign of hormonal imbalance caused by periods, pregnancy or PCOS. Hormonal therapies can often benefit women whose acne flares up around their period or is associated with hormonal conditions such as PCOS. The combined oral contraceptive pill may be recommended, and may take up to a year before full benefits are seen. The BAD adds that pills containing cyproterone acetate may help women with hormone imbalances, and carry a small risk of blood clots.

In pregnancy, safety matters. The BAD says that isotretinoin can harm an unborn child, and that people who are able to get pregnant must enrol in a pregnancy prevention programme with a negative pregnancy test before starting and reliable contraception during treatment, and for at least four weeks after. It also says that some antibiotics cannot be taken if you are pregnant, so you should let your doctor know if you are planning a pregnancy.

The BAD says acne can leave scars or marks, particularly where nodules and cysts have developed. Scars may be raised and lumpy or indented (pitted), and the skin can be left red or darker or lighter than usual. NHS inform says any type of spot can lead to scarring, more so when nodules and cysts burst, and picking or squeezing increases the risk.

Acne can significantly affect psychological wellbeing. The BAD says it may lead to low self-esteem, anxiety and depression, and recommends speaking with a healthcare professional about available support if you need it. NICE says acne that is causing or contributing to persistent psychological distress is a reason to consider referral to a dermatologist-led team.

The NHS says to see a GP if you have tried to treat acne yourself and it is not getting better, you have lots of spots or the spots are deep, painful or causing scars, you have signs of a skin infection such as hot, swollen and red skin, or it is affecting your mental health. A GP may offer prescription treatments or refer you to a dermatologist.

NICE says referral to a consultant dermatologist-led team should be considered if mild-to-moderate acne has not responded to two completed courses of treatment, moderate-to-severe acne has not responded to previous treatment that includes an oral antibiotic, or there is scarring or persistent pigment changes. It also says acne fulminans, a severe form, needs urgent same-day referral to the on-call hospital dermatology team.

Not all spots are acne. The BAD says that if there is something unusual about the rash, you should consult a healthcare professional. If acne appears suddenly or gets worse after starting a new medicine, discuss it with your healthcare professional.

On the NHS the route is usually the pharmacy, then the GP, then dermatology if needed. NHS inform says a pharmacist can diagnose acne by looking at the skin and can treat it. The BAD says that isotretinoin can be prescribed only under the supervision of a dermatology healthcare professional, and that laser resurfacing, chemical peels, microneedling and subcision for scarring are not routinely available on the NHS.

Private dermatology services and aesthetic clinics offer these scar treatments and prescription treatments with shorter waits. The BAD notes that laser treatment should not be carried out for at least one year after completing a course of isotretinoin, so tell any practitioner about past treatment.