Spots appear usually on the face, back and chest, when hair producing follicles and oil glands become inflamed or blocked.
Hormone changes at puberty are one of the triggers for acne. Production of the male sex hormone testosterone increases at this time and causes the sebaceous glands in the skin to produce more oil (sebum).
The lining of hair-producing follicles also thickens during puberty, leading to blocked pores. This increase in oiliness triggers a reaction in a usually harmless skin bacteria called P. acnes, causing inflamed (red) skin.
Acne runs in families, so if your parents had it you're more likely to develop the condition. It's a myth acne is associated with not washing, in fact, excessive washing and scrubbing can make acne worse.
Acne can flare up at any age. Over 80 per cent of adult acne cases are in women and it most commonly appears during pregnancy or the menopause, but around 70 per cent of women notice a worsening of acne just before their monthly period.
Diet was previously believed to have no effect on acne, but recent research has found eating lots of sugary carbohydrates may play a role after all . There's some evidence foods with a low glycaemic load (complex carbohydrates such as wholegrains, fruits and vegetables) may improve acne.
Greasy, oily skin is a symptom of acne. Your skin may also feel hot and be tender to touch.
Acne includes blackheads, whiteheads, papules (small red bumps), pustules (red bumps with a white tip), nodules (large, hard lumps below your skin) and cysts (large, pus-filled lumps like boils).
In more severe cases, large spots, especially cysts, may burst and can leave scars. This is known as cystic acne and accounts for around one in five acne cases.
Acne is normally graded from 1-4 . Grade 1 is mild, mostly blackheads and whiteheads. Grade 2 is moderate, with papules and pustules, mostly on your face. Grade 3 is moderately severe, with lots of papules and pustules, a few inflamed nodules, with back and chest affected too. Most severe is Grade 4, with lots of large, painful pustules and nodules.
If you’re an adult woman experiencing acne for the first time, your doctor may order tests to find out if Polycystic Ovary Syndrome (PCOS) could be to blame. PCOS sufferers have high levels of testosterone which can increase oil production.
Who gets acne?
Acne is most common in teenagers and young adults, affecting 80 per cent of people between ages 11 and 30, and the average age for acne to start is 15 for boys and 16 for girls.
Adults get acne too, with around five per cent of women and one per cent of men over 25 affected.
Mild acne can be treated with over-the-counter (OTC) creams and gels. Look for those containing benzyl peroxide, an anti-bacterial which helps reduce the number of spots and has an anti-inflammatory effect.
Creams and gels containing azelaic acid are also available over the counter, such as products with nicotinamide that contain a vitamin B complex which has an anti-inflammatory effect. All acne treatments take at least two months to work effectively, so it’s important to persevere.
Your GP or dermatologist can prescribe a retinoid cream (derived from vitamin A) – tretinoin or adapalene – which works by exfoliating dead skin cells and unblocking hair follicles.
For severe acne, antibiotic creams or tablets can be prescribed. However, there's been concern recently about antibiotic-resistant acne bacteria developing. The contraceptive pill is also sometimes prescribed for acne and has been found to be effective as it can help to restore hormonal imbalances which can make acne worse.
Dermatologists or specialist dermatology GPs can prescribe isotretinoin, which works by reducing oil production, preventing clogged follicles and reducing bacteria. Because of side-effects though, it is reserved for those who have failed on other treatments.
Other options include lasers, blue light treatment or a hormone pill called co-cyoprindol.