What causes acne and why does it keep coming back?

Acne vulgaris develops when androgen-driven sebum production, follicular hyperkeratinisation, Cutibacterium acnes colonisation, and inflammation combine in the pilosebaceous unit. It tends to persist or recur because the underlying hormonal and inflammatory drivers are ongoing — particularly in adult women with menstrual-cycle fluctuations, polycystic ovary syndrome, or perimenopause. Stress, certain medications (corticosteroids, B12, anabolic steroids), and high-glycaemic dietary patterns may also contribute. Treatment addresses the drivers rather than eliminating the tendency permanently, though isotretinoin can produce sustained remission in severe disease after a full course.

Which topical treatments should I use and in what order?

Start with a topical retinoid (adapalene 0.1% or tretinoin 0.025–0.05%) at night — begin two to three nights per week to build tolerance, then increase to nightly. Apply benzoyl peroxide in the morning to the same areas. For inflammatory lesions add topical clindamycin 1% — always as a fixed combination with benzoyl peroxide (Duac or equivalent) to prevent antibiotic resistance. Azelaic acid 15–20% is an alternative, safe in pregnancy. Expect 8–12 weeks before full benefit. Use non-comedogenic moisturiser and SPF 50+ sunscreen daily, as retinoids increase photosensitivity.

What is isotretinoin and who needs it?

Isotretinoin (Roaccutane and generics) is an oral vitamin A derivative targeting all four acne pathways — sebum suppression, follicular normalisation, anti-inflammatory activity, and anti-microbial effect. It is indicated for severe nodulocystic or scarring acne, acne refractory to other treatments, and cases causing profound psychological burden. In Australia it is PBS Authority Required. Side effects include universal mucosal dryness, potential hyperlipidaemia, transaminitis, and a TGA Boxed Warning for depression and suicidality. It is Pregnancy Category X — strict contraception is mandatory for one month before, throughout, and one month after the course.

Are hormonal treatments effective for adult female acne?

Yes — hormonal therapies are highly effective for adult female acne, particularly jawline and chin-distributed acne tied to the menstrual cycle or polycystic ovary syndrome. Combined oral contraceptives with anti-androgenic progestogens (drospirenone — Yaz/Yasmin; cyproterone — Diane-35/Brenda-35) suppress androgen-driven sebum. Diane-35 and Brenda-35 are PBS Authority items for severe acne. Spironolactone 50–200 mg daily is used off-label with approximately 80% effectiveness; it requires pregnancy avoidance (Category B3) and baseline electrolytes. These are appropriate first-line systemic choices in adult women without contraindications.

How can I reduce the risk of acne scarring?

The most effective scar-prevention strategy is controlling acne early and avoiding picking or squeezing lesions, which deepens inflammation and worsens postinflammatory hyperpigmentation. Topical retinoids reduce comedonal load. For moderate-to-severe inflammatory and nodulocystic acne — the subtypes most likely to scar — stepping up therapy promptly is important. SPF 50+ sunscreen daily reduces the visibility of postinflammatory hyperpigmentation. Once acne is controlled for at least three to six months, established scars (atrophic ice-pick, boxcar, rolling, or hypertrophic) can be assessed by a dermatologist for procedural revision including microneedling, fractional laser, subcision, and dermal fillers.

Acne vulgaris

Acne vulgaris: stepwise treatment in Australian general practice

By Dr HB Lo, FACRRM Reviewed 2 June 2026 8 min read

Acne vulgaris is a chronic inflammatory skin disease affecting around 85% of adolescents and 50% of adult women, producing comedones, papules, pustules, nodules, and scarring with substantial psychological burden.

Treatment is stepwise. Topical retinoids and benzoyl peroxide form the foundation; topical antibiotics are always combined with benzoyl peroxide to prevent resistance. Oral doxycycline covers moderate inflammatory acne for up to three months. Adult female acne often responds to hormonal options — combined oral contraceptive or spironolactone. Severe or scarring acne is the domain of isotretinoin, which needs strict pregnancy prevention and regular monitoring.

Acne vulgaris is one of the most common conditions encountered in Australian general practice. It affects approximately 85% of adolescents at some point and persists or recurs in around 50% of adult women, with rates of adult-onset acne rising. Beyond its physical manifestations — the spectrum of comedones, papules, pustules, nodules, cysts, and scars that characterise the condition — acne carries substantial psychological weight, with validated associations with depression, anxiety, and reduced quality of life. The Australasian College of Dermatologists recognises acne as a genuine chronic disease requiring stepwise management rather than a cosmetic inconvenience.

The pathophysiology involves four interacting processes: androgen-stimulated sebum overproduction, follicular hyperkeratinisation leading to comedone formation, colonisation of the pilosebaceous unit by Cutibacterium acnes (formerly Propionibacterium acnes), and innate and adaptive immune-mediated inflammation. Any effective treatment programme works by addressing one or more of these pathways.

A. Core clinical — the AU general-practice framework

Classification

Therapeutic Guidelines (eTG) and the Australasian College of Dermatologists classify acne by morphology and severity, which directly guides treatment decisions.

Comedonal acne — open comedones (blackheads, with oxidised melanin at the surface) and closed comedones (whiteheads). Non-inflammatory; responds primarily to topical retinoids.

Inflammatory acne — papules (solid, raised, ≤5 mm) and pustules (raised, pus-containing). Driven by C. acnes and the immune response. Topical antibiotics combined with benzoyl peroxide are added to the retinoid foundation.

Nodulocystic acne — deep, painful nodules and cysts ≥5 mm. High scarring risk; often requires oral therapy or isotretinoin.

Adult-onset / persistent female acne — predominantly inflammatory; jawline, chin, and lower-face distribution; hormonal drivers prominent.

Drug-induced acneiform eruptions — from corticosteroids, anabolic steroids, EGFR inhibitors, lithium, B12, isoniazid; typically uniform monomorphic pustules without comedones.

History

A thorough history shapes treatment selection. Key domains:

Onset and duration: adolescent-onset versus adult or late-onset
Lesion types and distribution: comedonal versus inflammatory versus nodulocystic; face, chest, back
Scarring: atrophic (ice-pick, boxcar, rolling) versus hypertrophic or keloidal; significant in choosing treatment urgency
Psychosocial impact: depression screen (PHQ-2), body image, work or social avoidance
Hormonal context (women): menstrual regularity, hirsutism, oligomenorrhoea, weight change, fertility planning — screen for PCOS
Medications: topical steroids, testosterone (athletes, gender-diverse patients), anabolic steroids, corticosteroids, B12, lithium
Prior treatments and response: retinoids, antibiotics, hormonal contraception, isotretinoin
Pregnancy or planning: critical before prescribing retinoids or isotretinoin

Examination

Assess lesion type, distribution, and severity. Document the presence of comedones — their absence distinguishes rosacea from acne. Look for scarring type and extent. In women where hormonal acne is suspected, examine for hirsutism (Ferriman–Gallwey scale), weight, and clinical PCOS features.

Investigations

Most acne is a clinical diagnosis requiring no investigation.

Hormonal workup (if hyperandrogenism, PCOS, or late-onset adult female acne suspected): testosterone (total and free), SHBG, DHEAS, 17-OH progesterone, LH/FSH, prolactin, TSH. MBS item 66716 (TSH); others as indicated.

Pre-isotretinoin baseline: FBC 65070, liver function tests 66512, fasting lipids 66536, and pregnancy test (β-hCG 66635) at initiation and monthly thereafter in women of childbearing potential.

Pre-spironolactone: UEC 66500 for baseline potassium.

Differential diagnosis

Condition	Key discriminator
Rosacea	No comedones; central-face erythema and flushing; adult onset
Perioral dermatitis	Perioral/perinasal distribution; linked to topical steroid use
Folliculitis	Monomorphic pustules; culture may grow Staphylococcus aureus or Pityrosporum
Steroid acneiform eruption	Uniform lesions; no comedones; steroid history
Hidradenitis suppurativa	Axillae, groin, perianal; sinuses and scarring; follicular occlusion tetrad
Drug-induced acne	Corticosteroids, B12, anabolic steroids; monomorphic; drug history

B. Evidence appraisal — topical foundations to systemic escalation

Topical retinoids and benzoyl peroxide

eTG: Dermatology and AMH both position topical retinoids as the cornerstone of acne management across all severities. Retinoids (adapalene 0.1%, tretinoin 0.025–0.05%, tazarotene) normalise follicular keratinisation, reduce comedone formation, and have an anti-inflammatory effect. Adapalene is generally better tolerated for initiation.

Benzoyl peroxide (BPO) 2.5–10% is bactericidal against C. acnes and comedolytic. It is available over the counter. BPO does not induce resistance — a critical advantage over topical antibiotics. Using BPO at least in the morning alongside any topical antibiotic regime prevents the emergence of antibiotic-resistant C. acnes.

The antibiotic resistance imperative

NPS MedicineWise and eTG both emphasise that topical antibiotics should never be used as monotherapy. Topical clindamycin 1% or erythromycin 2% must always be prescribed as a fixed combination with BPO (Duac — clindamycin/BPO; Epiduo — adapalene/BPO). Oral antibiotics should be used for no more than three months, then transitioned to topical maintenance. This prevents the emergence of resistant C. acnes strains, which are documented globally and render topical antibiotic therapy ineffective.

Oral doxycycline

For moderate-to-severe inflammatory acne, oral doxycycline 50–100 mg daily (or minocycline as an alternative, with caution regarding drug-induced lupus and hyperpigmentation) is appropriate for up to three months. The combination of oral antibiotic + topical retinoid + BPO gives the best outcomes. On completion of the antibiotic course, maintenance with topical retinoid + BPO continues.

Isotretinoin evidence

Isotretinoin is uniquely effective — the only treatment addressing all four acne pathways. It produces long-term remission in approximately 85% of patients after a full course (cumulative dose ~120–150 mg/kg over 16–20 weeks). The TGA Boxed Warning for depression and suicidal ideation requires mood monitoring at every visit, though multiple cohort studies suggest severe untreated acne itself is a stronger driver of suicidality than isotretinoin. The evidence does not support withholding isotretinoin from appropriate candidates on the basis of mood risk alone — but concurrent mental health support and vigilance are mandatory.

C. Stepwise pharmacotherapy guide

Mild comedonal acne

Foundation: topical retinoid nightly + BPO morning. Begin retinoid two to three nights per week, increase over four weeks to nightly as tolerance develops. Expect 8–12 weeks for visible improvement. Counsel on photosensitivity (use SPF 50+ sunscreen daily) and initial dryness/peeling.

Mild-to-moderate inflammatory acne

Add: topical clindamycin 1% + BPO (fixed combination) applied morning. Azelaic acid 15% gel is an alternative with anti-inflammatory and comedolytic activity — it is pregnancy-safe and reduces postinflammatory hyperpigmentation.

Moderate-to-severe inflammatory acne

Step up to: oral doxycycline 50–100 mg daily for up to three months, continuing topical retinoid + BPO. At three months, cease oral antibiotic and maintain with topicals alone.

Hormonal acne in adult women

Where premenstrual flares, jawline predominance, or PCOS features point to an androgenic driver, add:

Combined oral contraceptive with anti-androgenic progestogen (drospirenone — Yaz/Yasmin; cyproterone — Diane-35/Brenda-35). PBS lists Diane-35/Brenda-35 as Authority Required for severe acne. Counsel on VTE risk (higher with cyproterone than levonorgestrel-based pills).
Spironolactone 50–200 mg daily (off-label) — approximately 80% effective. Monitor UEC at baseline; avoid in pregnancy (Category B3 — theoretical risk of feminisation of male fetus). Potassium monitoring in patients co-prescribed ACE inhibitors or ARBs.

Severe, nodulocystic, or scarring acne

Isotretinoin (Roaccutane, generics): 0.5–1 mg/kg/day for 16–20 weeks; cumulative dose ~120–150 mg/kg. PBS Authority Required (Streamlined) for severe acne. Key management steps:

Exclude pregnancy (negative β-hCG) and counsel on Pregnancy Category X status — effective contraception required one month before, throughout, and one month after the course
Baseline LFT and fasting lipids — repeat at 6–8 weeks
Monthly β-hCG in women of childbearing potential during the course
Mood assessment at every visit; document
Avoid concurrent tetracycline (pseudotumour cerebri risk)
Counsel on universal dryness (lips, skin, eyes, nasal mucosa) — moisturiser, lip balm, eye drops
SPF 50+ sunscreen mandatory

D. Australian operations

PBS listings (verified pbs.gov.au 2026)

Topical retinoids (adapalene, tretinoin): general schedule
Benzoyl peroxide: over the counter
Topical antibiotics and fixed combinations (clindamycin, Duac, Epiduo): general schedule
Oral antibiotics (doxycycline, minocycline): general schedule
Isotretinoin (Roaccutane, generics): Authority Required (Streamlined) for severe acne
Diane-35/Brenda-35 (cyproterone + ethinyloestradiol): Authority Required for severe acne
Yaz/Yasmin (drospirenone + ethinyloestradiol): general schedule
Spironolactone: general schedule (off-label for acne)
Azelaic acid: general schedule

MBS billing

Standard consults: 23 / 36 / 44.

GPMP/TCA (721/723): where acne is part of a complex chronic disease plan (e.g., PCOS + acne + metabolic risk).

Mental Health Care Plan (2715/2717): appropriate where acne is causing clinically significant depression, anxiety, or body image disturbance — particularly on isotretinoin, where mood monitoring is mandatory.

Documentation and medico-legal points

Isotretinoin prescribing requires meticulous documentation: consent (teratogenicity, mood, dryness, monitoring requirements), pregnancy test results at each visit, discussion of contraception, and assessment of mood. Some practices use a standardised isotretinoin checklist. Monthly pregnancy testing is not optional for women of childbearing potential.

Topical antibiotic prescribing should document the antimicrobial stewardship rationale — maximum three months oral antibiotics, always with BPO.

E. Special populations

Pregnancy and lactation

Topical retinoids are teratogenic — avoid. Azelaic acid 15% (Category B2) and topical clindamycin/BPO are generally considered acceptable. Oral erythromycin is preferred over tetracyclines (avoided in second and third trimester — teeth and bone effects) for moderate inflammatory acne in pregnancy. Isotretinoin is absolutely contraindicated (Category X).

Adolescents

Start with topical foundations; be attentive to adherence and psychosocial impact. Body image concerns, depression, and school-related avoidance are common and can be addressed via a Mental Health Care Plan referral to psychology.

Skin of colour

Postinflammatory hyperpigmentation is more prominent in darker skin tones (Fitzpatrick IV–VI). Azelaic acid and retinoids both help. Advise consistent daily SPF 50+ sunscreen. Avoid aggressive procedures (chemical peels, lasers) until acne is controlled — risk of hyperpigmentation is higher in active inflammatory disease.

Gender-diverse patients

Testosterone use in trans men significantly exacerbates acne. Management may include topical foundations, oral antibiotics, and isotretinoin when needed. Hormonal contraceptive options require consideration of gender-affirming care context; consult with the patient’s gender-affirming health team.

When to escalate

Refer or escalate when:

Severe nodulocystic or widespread scarring acne requiring isotretinoin (if not GP-initiated)
Suspected hyperandrogenism or PCOS requiring gynaecological/endocrine workup
Acne fulminans (acute severe ulcerating lesions with systemic features — fever, arthralgia) — emergency dermatology
Significant psychiatric burden — body dysmorphic disorder, severe depression, or suicidal ideation associated with acne
Refractory acne not responding to appropriate stepwise management
Scarring requiring procedural revision (dermatology, after acne is controlled)

Choosing Wisely Australia recommends against long-term oral antibiotic use (beyond three months) without reassessment and documented reason.

What this article is and is not

This is general health information drawn from current Australian general practice guidelines — eTG: Dermatology, AMH, Australasian College of Dermatologists, RACGP, and NPS MedicineWise. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about specific treatments — including isotretinoin, hormonal therapies, and pregnancy management — are made with your own GP and treating clinicians.

Consumer resources: HealthDirect — Acne, Better Health Channel — Acne, Australasian College of Dermatologists — Consumer.

Sources cited

Frequently asked questions

What causes acne and why does it keep coming back?

Acne vulgaris develops when androgen-driven sebum production, follicular hyperkeratinisation, Cutibacterium acnes colonisation, and inflammation combine in the pilosebaceous unit. It tends to persist or recur because the underlying hormonal and inflammatory drivers are ongoing — particularly in adult women with menstrual-cycle fluctuations, polycystic ovary syndrome, or perimenopause. Stress, certain medications (corticosteroids, B12, anabolic steroids), and high-glycaemic dietary patterns may also contribute. Treatment addresses the drivers rather than eliminating the tendency permanently, though isotretinoin can produce sustained remission in severe disease after a full course.
Which topical treatments should I use and in what order?

Start with a topical retinoid (adapalene 0.1% or tretinoin 0.025–0.05%) at night — begin two to three nights per week to build tolerance, then increase to nightly. Apply benzoyl peroxide in the morning to the same areas. For inflammatory lesions add topical clindamycin 1% — always as a fixed combination with benzoyl peroxide (Duac or equivalent) to prevent antibiotic resistance. Azelaic acid 15–20% is an alternative, safe in pregnancy. Expect 8–12 weeks before full benefit. Use non-comedogenic moisturiser and SPF 50+ sunscreen daily, as retinoids increase photosensitivity.
What is isotretinoin and who needs it?

Isotretinoin (Roaccutane and generics) is an oral vitamin A derivative targeting all four acne pathways — sebum suppression, follicular normalisation, anti-inflammatory activity, and anti-microbial effect. It is indicated for severe nodulocystic or scarring acne, acne refractory to other treatments, and cases causing profound psychological burden. In Australia it is PBS Authority Required. Side effects include universal mucosal dryness, potential hyperlipidaemia, transaminitis, and a TGA Boxed Warning for depression and suicidality. It is Pregnancy Category X — strict contraception is mandatory for one month before, throughout, and one month after the course.
Are hormonal treatments effective for adult female acne?

Yes — hormonal therapies are highly effective for adult female acne, particularly jawline and chin-distributed acne tied to the menstrual cycle or polycystic ovary syndrome. Combined oral contraceptives with anti-androgenic progestogens (drospirenone — Yaz/Yasmin; cyproterone — Diane-35/Brenda-35) suppress androgen-driven sebum. Diane-35 and Brenda-35 are PBS Authority items for severe acne. Spironolactone 50–200 mg daily is used off-label with approximately 80% effectiveness; it requires pregnancy avoidance (Category B3) and baseline electrolytes. These are appropriate first-line systemic choices in adult women without contraindications.
How can I reduce the risk of acne scarring?

The most effective scar-prevention strategy is controlling acne early and avoiding picking or squeezing lesions, which deepens inflammation and worsens postinflammatory hyperpigmentation. Topical retinoids reduce comedonal load. For moderate-to-severe inflammatory and nodulocystic acne — the subtypes most likely to scar — stepping up therapy promptly is important. SPF 50+ sunscreen daily reduces the visibility of postinflammatory hyperpigmentation. Once acne is controlled for at least three to six months, established scars (atrophic ice-pick, boxcar, rolling, or hypertrophic) can be assessed by a dermatologist for procedural revision including microneedling, fractional laser, subcision, and dermal fillers.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.

T1 AU primary 10 sources