Why does acne exist?

What happens inside a pore?

A pore opens into a hair follicle containing a hair and an oil gland. The gland produces sebum, the skin's natural oil, which helps carry away old skin cells and keeps skin soft. Skin oil has a useful job, despite the skincare industry's enthusiasm for treating it as an administrative error. Oil and skin cells can collect into a plug called a comedone: a whitehead or blackhead.3

Bacteria trapped in a blocked follicle can trigger an immune response, producing inflammation and pus. Inflammation also contributes to blockage, so acne is not simply a cork in an otherwise quiet pore. The follicle wall can rupture and increase inflammation. Deeper acne can produce painful lumps rather than small surface bumps.134

Why is acne so common during puberty?

During puberty, hormones called androgens enlarge the oil glands and increase oil production. More oil can contribute to clogged pores. Nearly everyone gets at least a few teenage breakouts, but having a close blood relative with severe, scarring acne increases the risk of developing severe acne yourself. Differences in the immune system and its inflammatory response also help explain differences in severity.45

Why do adults still get acne?

Acne can continue into the 30s, 40s and 50s or begin for the first time in adulthood, because oil glands do not recognise graduation certificates. Adult acne is more common in women. Hormone changes around periods, pregnancy, menopause, and starting or stopping birth control pills can contribute. Family history, skin and hair products, certain medicines, and sometimes an underlying medical condition also play a part.6

Is acne caused by dirt, stress or food?

Blackheads and pimples are not caused by dirt, so acne is not a failed cleanliness inspection. Stress can worsen existing acne rather than being its sole cause. Too little sleep, oily skincare or hair products, humidity, and repeated pressure or rubbing can also contribute to flare ups.357

Chocolate and greasy food are often blamed, but research does not show that they cause acne. Dairy and foods high in refined sugars have been linked with acne in some people, although the connection remains uncertain. Diet is difficult to study, and changing what you eat does not always improve acne.34

What can you do about the causes?

• Wash gently twice a day and remove makeup at the end of the day. Do not scrub: irritation can make acne worse.
• Choose skincare, makeup and hair products labelled noncomedogenic, meaning formulated not to clog pores. These are less likely to contribute to acne.
• Avoid picking or squeezing spots, which can cause scars. For body acne, wear loose, breathable clothing, especially during exercise.
• Ask a pharmacist about acne treatments such as benzoyl peroxide or salicylic acid. Follow the product directions rather than applying extra.
• If a medicine seems to trigger breakouts, keep taking it and speak with the prescriber about alternatives.

Acne treatments target different parts of the process: blocked follicles, bacteria, inflammation, oiliness or hormone effects. Treatment responses can take 6 to 8 weeks. Products applied to the skin can cause redness, dryness or excessive peeling.13

See a doctor if acne is deep, painful, leaving scars, not improving with treatment, or affecting your mental health. Hot, swollen or red skin can indicate infection and also needs medical assessment. Prescription treatments or a referral to a dermatologist are options.1

Why does acne eventually clear?

Acne often improves after age 25, but it can persist. Why it eventually clears is not fully understood: improvement does not always coincide with less oil or fewer bacteria. Changes in the oil glands or immune activity are possible explanations.24