Acne

Acne is one of the commonest skin conditions, and most people have it at some point. The tiny glands beside hair follicles make an oil called sebum that keeps skin supple. In acne these glands make too much sebum, dead skin cells build up, and the follicle becomes blocked.

Bacteria that live harmlessly on skin then multiply inside the blocked follicle, and the skin around it becomes inflamed, swollen and sometimes painful. Acne is usually at its most active in the teens and twenties, but it can start or continue later, and it can be controlled with treatment.

Acne mostly affects the face, and often the back and the chest as well. Skin may feel oily, and sore or hot to touch. The spots take several forms:

• Blackheads: small open plugs that darken at the surface
• Whiteheads: small firm bumps under the skin surface
• Papules: small red or darker tender bumps
• Pustules: similar bumps with a white or yellow pus-filled tip
• Nodules: large, hard, painful lumps deeper in the skin
• Cysts: large pus-filled lumps, the type most likely to scar

See a doctor in the next few days for deep painful lumps or cysts, for acne on the chest or back, for acne that has not improved with a pharmacy treatment used as directed, for spots that are scarring, or if the skin is affecting your mood or making you avoid people.

Acne is linked to hormonal change, particularly the rise in androgens during puberty, which enlarges the oil glands and increases sebum. The lining of the follicle also thickens, so the pore blocks more easily. Bacteria inside the blocked follicle then drive inflammation and pus.

Acne often runs in families. It can also be triggered or worsened by some medicines, including steroids, lithium and some hormone treatments, by hormonal conditions such as polycystic ovary syndrome, by greasy cosmetics and hair oils, and by pressure from helmets, straps or tight clothing.

• Being a teenager or young adult
• A parent, brother or sister who had acne
• Hormonal changes, including periods, pregnancy and polycystic ovary syndrome
• Certain medicines, such as steroids and lithium
• Oily cosmetics, hair oils and thick sunscreens applied to the face
• Pressure and rubbing from helmets, collars, masks or straps
• Humid, polluted or dusty surroundings, and heavy sweating
• Picking or squeezing spots, and scrubbing the skin hard

Scarring is the main physical complication. Scars may be small deep pits, wider shallow depressions or a rolling, uneven surface, and they follow nodules and cysts or the habit of squeezing spots. Dark marks left after a spot heals are common on brown and black skin and usually fade slowly over months.

Acne also affects how people feel. It can cause intense anxiety and stress, make people withdraw from others, and lead to depression. If you or your child have felt low, hopeless or uninterested in things for weeks, tell a doctor, because that can be treated as surely as the skin can.

• Wash the affected skin no more than twice a day with a mild cleanser and lukewarm water
• Do not scrub hard, and avoid harsh or gritty face washes
• Leave spots alone rather than squeezing or picking them
• Choose make-up, sunscreen and moisturisers labelled oil free or non-comedogenic
• Keep hair oils off the face and forehead, and wash hair regularly if it is oily
• Shower and change clothes soon after sweating heavily
• Remove make-up completely before sleeping

A doctor diagnoses acne by looking at the skin and noting the type, number and site of the spots, which sets the severity and the treatment. Tests are not usually needed.

Questions cover how long it has been there, what has been tried, family history, medicines in use, and, for women, periods, hair growth and pregnancy plans. Blood or hormone tests are arranged when an underlying hormonal condition is suspected, such as acne starting suddenly in an adult.

Acne cannot be cured but it can be controlled. Mild acne is often treated with products from a pharmacy, such as benzoyl peroxide, which reduces bacteria and unblocks pores. Doctors also prescribe creams and gels based on vitamin A, antibiotic creams and azelaic acid. These can dry or irritate the skin at first, and some make the skin more sensitive to sunlight.

For moderate to severe acne, antibiotic tablets are used together with a treatment applied to the skin, usually for a few months rather than indefinitely, because bacteria can become resistant. For some women a combined hormonal contraceptive pill helps hormonal acne, and other hormone-blocking medicines are an option.

Severe acne that does not respond is treated by a skin specialist with a strong vitamin A based tablet, under careful supervision. It must never be taken in pregnancy because it causes serious birth defects, and it needs strict precautions and review. Scars may later be improved with procedures such as chemical peels, microneedling, laser treatment or injections. Treatments take about six weeks to three months to show their effect.