Acne Vulgaris

Inflammatory condition of the pilosebaceous unit

Aetiology

  • Age 12-24
  • Family history
  • Associated with some endocrine disorders: PCOS, hyperandrogenism

Pathophysiology

  1. Increased androgens at puberty; patients may have increased androgen sensitivity of sebaceous glands
  1. Hypercornification causes keratin plugging of pilosebaceous units
  1. Infection with corynebacterium acnes (anaerobic bacterium)
  1. Keratin and sebum build up to produce comedones (whiteheads/blackheads)
    1. Sebum production can be caused by increased androgens
  1. Rupture causes acute inflammation and foreign body granulomas - produces the inflammatory lesions (papules, pustules, cysts and nodules)

Clinical presentation

  • Distribution reflects sebaceous gland sites - face, upper back, anterior chest
  • Non-inflammatory lesions (comodones) - blackheads and whiteheads
  • Inflammatory lesions - papules, pustules, cysts, nodules on erythematous base
  • Complications of chronic acne:
    • Atrophic scars - ice pick scars or hypertrophic keloid scars
    • Skin hyperpigmentation
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Classification of acne

  • Mild: scattered comodones, papules and pustules
  • Moderate: numerous papules, pustules and mild atrophic scarring
  • Severe: numerous papules, pustules, severe atrophic scarring, cysts, nodules

Management

Mild-moderate acne

  • Topical treatment for 3/12 then review:
    • Benzoyl peroxide
    • Retinoids - adapalene, isotretinoin, tretinoin
    • Topical antibioic combined with benzoyl peroxide, retinoids or zinc to reduce antimicrobial resistance
  • If poor response to topical treatment at 3 month review consider systemic treatment
    • Under 12 - erythromycin or clarithromycin BD
    • 12 and over - lymecycline OD OR doxycycline OD OR erythromycin/clarithromycin BD

Severe cystic acne

  • Commence systemic antibiotic therapy and refer immediately for consideration of systemic isotretinion treatment (roaccutane)