What is acne?
Acne develops when hair follicles become blocked with oil (sebum) and dead skin cells, allowing acne-related bacteria to multiply and trigger inflammation. It ranges from mild comedonal acne (blackheads and whiteheads) through to more severe inflammatory and cystic acne, which carries the highest risk of permanent scarring.
While most associated with the teenage years, adult acne — particularly in women in their 20s and 30s — is increasingly common and often hormonally driven.
Causes and triggers
- Excess oil (sebum) production, often hormonally driven.
- Blocked pores from a build-up of dead skin cells.
- Bacterial overgrowth within blocked follicles, triggering inflammation.
- Hormonal changes — puberty, the menstrual cycle, pregnancy, and conditions like PCOS.
- Genetics — a family history of acne increases your risk.
- Certain medications and comedogenic cosmetics.
Diet's role is debated, but high-glycaemic foods and, in some people, dairy appear to worsen acne.
Signs and severity
- Blackheads and whiteheads (comedones).
- Red, inflamed papules and pustules.
- Deeper, painful cysts or nodules — the type most likely to scar.
- Oily skin, and dark marks or pitting after lesions heal.
See a doctor promptly if
Your acne is cystic, painful, or leaving marks and scars. Early treatment is the single best way to prevent permanent scarring — waiting it out is rarely the right approach for moderate-to-severe acne.
Diagnosis
Acne is usually diagnosed by examination alone. Your doctor will assess the lesion type and severity to guide treatment, and consider underlying hormonal drivers if the pattern suggests it — for example, sudden adult-onset acne alongside other features of PCOS.
Treatment options
Topical treatments
Retinoids, benzoyl peroxide and topical antibiotics are first-line for mild-to-moderate acne.
Oral antibiotics
Short courses for moderate inflammatory acne not responding to topicals alone.
Hormonal treatment
The oral contraceptive pill or spironolactone can help hormonally driven adult acne in women.
Specialist referral
Severe, cystic, or scarring acne is referred for consideration of isotretinoin under specialist supervision.
Self-care tips
- Use gentle, non-comedogenic skincare — avoid over-washing or scrubbing, which can worsen inflammation.
- Choose a non-comedogenic, broad-spectrum sunscreen daily.
- Resist picking or squeezing lesions, which raises the risk of scarring.
- Be patient — most treatments take 6–8 weeks to show visible improvement.
Frequently asked questions
Does diet cause acne?
Diet alone doesn't cause acne, but high-glycaemic foods and, in some people, dairy can make it worse. It's worth noticing your own patterns, but skincare and medical treatment remain the mainstay of management.
Will acne go away on its own?
It often improves after the teenage years, but adult acne is common and can persist for years. Treating it — rather than waiting — reduces both the duration of breakouts and the risk of lasting scars.
What's the difference between acne and acne scars?
Acne refers to the active breakouts themselves — the papules, pustules and cysts. Acne scars are the textural changes (pitting or raised tissue) left behind after inflamed lesions heal, and often need separate treatment once the acne itself is under control.