Ask the expert: what causes acne and how is it treated?

Acne is a very common skin condition that causes oily, spotty skin, which may feel painful and warm to touch. It is most common in teenagers and those in their 20s. However, acne can also occur in your 30s, 40s and 50s eg women going through menopause can develop adult-onset acne.

What are the main symptoms of acne?

Acne causes your skin to become oily, spotty and in some cases, lumpy. The most common types of acne spots include: 

  • Blackheads — also known as open comedone, these are large, open pores in your skin that are clogged with bacteria, dead skin cells and sebum (oil produced by sebaceous glands in your skin)
  • Papules — red spots 
  • Pustules — yellow pus-filled spots 
  • Whiteheads — also known as closed comedones, these are closed pores in your skin that are clogged with bacteria, dead skin cells and sebum

In severe cases of acne, you may also develop painful lumps under your skin, in the form of pus-filled cysts or hard nodules, which can cause permanent scarring.

Which areas of the body does acne affect?

Most people will develop acne symptoms on their face. In teenagers, the forehead, nose and chin are usually affected. However, around half of people with acne develop symptoms on their back and in around 15%, on their chest. Acne can also occur on your shoulders and in adult women, it often affects the jawline, chin and neck.

What are the different types of acne?

The different types of acne are based on their symptoms and are broadly categorised into fungal acne, which is characterised by pustules and papules, hormonal acne, which is characterised by whiteheads and blackheads, cystic acne, which results in cysts and nodular acne, which causes nodules. 

You can have more than one type of acne at the same time eg you may have cystic and nodular acne. 

What causes acne?

Most types of acne are caused by your skin producing too much sebum, which prevents the efficient shedding of dead skin cells as they stick together. These dead cells and excess sebum consequently clog the pores in your skin. Blocked pores can then become infected with a bacterium called Propionibacterium.

Propionibacterium normally lives on your skin without causing any problems, however, in acne, this bacterium gets trapped inside blocked pores, where it multiplies in number. This triggers inflammation and the formation of papules and pustules. If inflammation worsens, cysts and nodules may develop.

Unlike cystic, hormonal and nodular acne, which are caused by excess sebum production and dead cells blocking pores, fungal acne is primarily caused by an overgrowth of Malassezia yeast, a type of fungus that normally lives on your skin.

Is acne hereditary?

You can develop acne whether or not acne runs in your family. However, if acne does run in your family, you are more likely to develop it.

Is acne hormonal?

Acne can be associated with hormonal changes, such as in teenagers going through puberty, women with polycystic ovary syndrome (PCOS), women going through perimenopause or menopause or just before a period. These hormonal changes can trigger excess sebum production, which can lead to acne. 

Bodybuilders who take steroids (a type of hormone) or individuals who take steroids as treatment for another health condition can develop acne as a side effect of steroid use. 

Can certain diets and lifestyle habits cause acne?

Smoking can worsen acne in adults and certain cosmetics can also trigger acne, although this is now less common due to the production of non-comedogenic cosmetics (ie cosmetics tested and proven not to trigger acne).

Although some individuals anecdotally find that removing certain foods from their diet improves their acne symptoms, there is currently not enough medical evidence to support this. Research is ongoing into whether following a low glycaemic index diet (ie a diet free from high-sugar foods and highly processed carbohydrates) can reduce acne symptoms.

How is acne diagnosed?

If you’re concerned that you may have acne, see your GP. They can reach a diagnosis after examining the affected areas of your skin.

How is acne treated medically?

There are several medical treatments for acne, which depend on your age, the severity of your acne and what treatment you have tried in the past.

Topical treatments (ie creams or gels that are applied directly to your skin) are often prescribed for mild to moderate acne. 

Your GP may prescribe a six to eight week course of topical antibiotics, which will destroy the bacteria on your skin. The topical antiseptic, benzoyl peroxide similarly destroys bacteria on your skin and also reduces inflammation. Topical retinoids may be prescribed to help remove dead cells, preventing them from blocking your pores. 

If you can’t tolerate topical retinoids or benzoyl peroxide, your GP may prescribe azelaic acid, which destroys bacteria and helps remove dead skin cells. 

Topical creams and gels may irritate your skin and cause redness. If you experience these side effects you should stop using your cream or gel for a while and then gradually restart treatment. If your side effects persist, see your GP so they can prescribe an alternative treatment. 

If you have more severe acne, in addition to topical treatment, your GP may prescribe a three to six month course of oral antibiotics. In adult women with acne, the oral contraceptive pill may be prescribed to treat the underlying hormonal imbalance causing their acne. 

If your acne fails to respond to any other treatments and/or is severe, your GP may refer you to a doctor who specialises in treating skin conditions (a dermatologist). 

Your dermatologist may prescribe isotretinoin capsules. Isotretinon decreases sebum production, helps prevent pores from becoming clogged and reduces inflammation, which subsequently also reduces bacteria levels on the skin. However, isotretinoin has many side effects, which is why it is only prescribed as a last line of treatment. 

How can I reduce my risk of acne breakouts?

You can reduce the frequency and severity of your acne breakouts through home remedies. This includes only using non-comedogenic cosmetic products and using these cosmetics — if you need to cover a spot, only use a powder-based (mineral) or water-based cosmetic. Also, remove any make-up before you go to bed.

It is also important to wash your face regularly (eg twice daily) with warm water. Although acne is not caused by dirty skin, washing helps as it removes excess sebum, which does cause acne.

However, you should not wash your face too often, as this can dry out your skin, triggering more sebum production, which will worsen your acne. Similarly, you should not wash your face too harshly as this can irritate your skin and worsen your acne symptoms.

You should also avoid too much exposure to the sun. Sunburn can dry your skin out, causing more dead skin cells and triggering more sebum production — both of which can trigger an acne breakout. To avoid this, make sure you wear non-comedogenic sunscreen.

Stress can also worsen acne symptoms, so try to avoid stressful situations and take part in activities that you know help you destress.

Author biography

Dr Namita Jasani is a Consultant Dermatologist at Spire Hartswood Hospital and Spire London East Hospital, specialising in acne treatment, skin infections and rashes, warts, skin cancers and hair disorders. Her sub-speciality is paediatric dermatology. She has a wealth of experience in a range of skin procedures, including skin biopsies, excision of skin cancers, moles, cysts and lipomas, curettage and cautery of viral warts, seborrheic keratosis and actinic keratosis, and shave excisions of skin tags, pyogenic granulomas and benign naevi.

We hope you've found this article useful, however, it cannot be a substitute for a consultation with a specialist

If you're concerned about symptoms you're experiencing or require further information on the subject, talk to a GP or see an expert consultant at your local Spire hospital.

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