Acne: Causes, Treatment, and What Actually Works for Every Skin Type

Four factors converge to produce acne, and understanding each one explains why different treatments target different steps:

1. Excess sebum production. Androgens (hormones like testosterone) stimulate the sebaceous glands to produce more oil. This is why acne peaks during puberty when androgen levels surge, and why hormonal acne is common in women around menstruation, pregnancy, and PCOS. The oil itself isn't 'bad' — but too much of it creates the environment for the next step.

2. Follicular hyperkeratinisation. Normally, dead skin cells lining the hair follicle shed and exit the pore. In acne-prone skin, these cells stick together and form a plug (a microcomedone). This is the earliest stage of all acne — a blocked pore that's not yet visible. Retinoids work by normalising this process.

3. Cutibacterium acnes proliferation. This bacterium is a normal skin inhabitant, but it thrives in the oxygen-poor, oil-rich environment of a blocked pore. As it multiplies, it triggers an immune response — the redness, swelling, and pus of inflammatory acne. Benzoyl peroxide and antibiotics target this step.

4. Inflammation. The immune system's response to C. acnes and the blocked pore produces the red, tender bumps, pustules, and deep nodules of inflammatory acne. In severe cases, this inflammation damages the dermis, producing the pitted scars that persist long after acne clears.

Genetics play a significant role — if both parents had acne, you're much more likely to experience it. Diet may contribute: high-glycemic foods (white bread, sugary drinks) and dairy have been associated with worsening in some studies, though the evidence isn't strong enough to recommend universal dietary restrictions.

Effective acne treatment targets one or more of the four underlying mechanisms — and the best approach depends on severity.

For mild acne (blackheads, whiteheads, occasional pimples):

Benzoyl peroxide (2.5–5%) kills C. acnes bacteria and reduces inflammation. It's available over the counter and is one of the most evidence-backed acne treatments. Start with a lower concentration to minimise irritation. It can bleach fabrics.

Topical retinoids (adapalene 0.1% is now available OTC in many countries; tretinoin and tazarotene by prescription) normalise skin cell turnover, unplug pores, and prevent new comedones from forming. They're the gold standard for maintenance treatment. Expect mild irritation and peeling initially — it improves after 2–4 weeks.

For moderate acne (multiple papules and pustules):

Combination therapy works best — typically a retinoid plus benzoyl peroxide, sometimes with a topical antibiotic (clindamycin) added for the first 3 months. Topical antibiotics should never be used alone due to resistance concerns.

For hormonal acne in women (typically along the jawline and chin, worse around periods):

Combined oral contraceptives reduce androgen-driven sebum production. Spironolactone (an anti-androgen) is highly effective for adult female acne and can be used long-term.

For severe acne (nodules, cysts, scarring):

Isotretinoin (formerly known as Accutane) is the most effective acne treatment available — it's the only medication that targets all four mechanisms simultaneously. A typical course lasts 5–6 months and produces long-term remission in the majority of patients. It requires strict monitoring (blood tests, pregnancy prevention) due to side effects, but for severe acne, the benefit-to-risk ratio is strongly favourable.

Regardless of severity, all acne treatments take 6–8 weeks to show improvement. Don't abandon a treatment before that window. Skin may temporarily worsen ('purging') in the first few weeks of retinoid use — this is normal and resolves.