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InflammatoryCommonICD-10 L70.x

Acne vulgaris

Acne · common acne

Acne vulgaris is an inflammatory pilosebaceous-unit disease affecting up to 85% of UK adolescents and persisting into adulthood in 20-40%. Pathogenesis involves four interacting factors: increased sebum (androgen-driven), abnormal follicular hyperkeratinisation, Cutibacterium acnes colonisation and inflammation. Important in skin-oncology because it is the principal DDx for EGFRi acneiform eruption, BRAFi papulopustular eruption, ICI acneiform reactions, and steroid-induced acne. NICE NG198 / 2021 underpins UK adult management.

CurrentLast reviewed 16 May 2026
Clinical image of Acne vulgaris
Acne vulgaris. Image sourced from DermNet New Zealand. Used under CC BY-NC-ND 4.0. No endorsement implied.

Pathogenesis

  • Four interacting factors:
    1. Increased sebum production (androgen-driven).
    2. Abnormal follicular hyperkeratinisation → comedone formation.
    3. Cutibacterium acnes (formerly Propionibacterium) colonisation.
    4. Inflammation — innate (TLR-2) and adaptive immune response.
  • Hormonal triggers: puberty, menstrual cycle, PCOS, androgen-secreting tumours, exogenous androgens / progestogens.
  • Diet (high glycaemic index, dairy) — emerging evidence.

Clinical features

  • Sites: face (forehead, cheeks, jawline), chest, upper back.
  • Lesion types:
    • Non-inflammatory: closed and open comedones (whiteheads / blackheads).
    • Inflammatory: papules, pustules, nodules, cysts.
    • Scarring: atrophic (ice-pick, rolling, boxcar), hypertrophic, keloid.
  • Severity:
    • Mild — comedonal ± few inflammatory.
    • Moderate — many inflammatory papules / pustules; scattered nodules.
    • Severe — multiple deep nodules / cysts; significant scarring.
  • Variants: acne fulminans (severe ulcerative + systemic), acne conglobata, drug-induced acne, occupational, mechanical (acne mechanica), pomade.
  • Adult acne: women predominantly; perimenstrual flare; mandibular distribution; hormonal pattern.

Differentials

  • Rosacea (papulopustular) — no comedones; central face; telangiectasia.
  • Perioral dermatitis — spares vermilion; less central face.
  • Folliculitis (bacterial) — uniform follicular pustules.
  • Pityrosporum folliculitis (Malassezia) — pruritic monomorphic follicular papulopustules.
  • EGFRi acneiform eruption — drug history; absent comedones; pruritic.
  • BRAFi / MEKi papulopustular eruption.
  • Steroid-induced acne — monomorphic; truncal; topical / oral steroid history.
  • Hidradenitis suppurativa — flexural; recurrent abscesses, sinus tracts.
  • Pyoderma faciale (rosacea fulminans).
  • Sycosis barbae, angiofibromas (tuberous sclerosis), milia.

Management (NICE NG198, 2021)

  • Lifestyle: gentle skincare, oil-free cosmetics; avoid pomades / occlusive sunscreens; sleep / stress / diet education.
  • Mild:
    • Topical adapalene 0.1% + benzoyl peroxide 2.5% (Epiduo) OD.
    • Topical clindamycin + benzoyl peroxide (Duac) OD.
    • Azelaic acid 15-20% BD (pregnancy-safe).
  • Moderate:
    • Topical retinoid + benzoyl peroxide + oral lymecycline 408 mg OD or doxycycline 100 mg OD for 8-12 weeks.
    • If acne-cycle relevance in women: combined OCP (oestrogen-containing); spironolactone 50-200 mg OD.
  • Severe / scarring / treatment-resistant:
    • Oral isotretinoin 0.3-1 mg/kg/day; cumulative target 120-150 mg/kg.
    • Requires baseline LFTs, lipids, pregnancy prevention and UK MHRA risk-minimisation monitoring.
  • Acne fulminans: oral isotretinoin + oral prednisolone overlap; specialist supervision.
  • Scarring: microneedling, fractional laser, dermal fillers, surgical revision after isotretinoin clearance.
  • Topical clascoterone: androgen-receptor blocker used in some markets; not a routine NHS acne treatment pathway.
  • EGFRi acne management: prophylactic doxycycline 100 mg BD on starting EGFRi; topical hydrocortisone 1%; emollients.

References

  1. NICE NG198. Acne vulgaris: management. London: NICE; 2021 (last updated 30 April 2026).
  2. Zaenglein AL et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol. 2016;74:945-973.
  3. Layton AM et al. Acne vulgaris and the role of isotretinoin. Br J Dermatol. 2022;187:1-12.
  4. Lacouture ME et al. Skin toxicity evaluation protocol with panitumumab (STEPP). J Clin Oncol. 2010;28:1351-1357.
  5. British Association of Dermatologists. Implementation guide to new isotretinoin prescribing changes. London: BAD; 2023; and Changes to isotretinoin prescribing: FAQs. London: BAD; 2026.

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