• A disorder of the Pilosebaceous Follicles
  • Incredibly common
    • Almost universal in the second decade of life
    • Also affects adults


  • A result of androgenic stimulation the sebaceous gland, causing:
    • Excessive sebum production
    • Obstruction of its outflow
    • Leakage into surrounding dermis*
    • Excessive colonisation or infection with Propionibacterium Acnes (a normal skin comensal)*
    • *Both cause the inflammation which produces the lesions
  • Tends to not be an excess of androgen but rather increased sensitivity to it, although:
    • Slight tendency towards boys (girls also experience it very frequently)
    • Boys may also experience it worse


  • Patient almost always an adolescent
  • Greasy skin


  • Open comedones (Blackheads)
  • Closed comedones (Whiteheads)
    • Obstructed pilosebaceous units
  • Papules (deep)
  • Pustules (more superficial)
  • Nodules
  • Cysts
    • Develop when there is further infection and inflammation due to P. Acnes


  • The face (almost universally)
  • Chest, neck and back
  • Course and severity are highly variable between individuals
  • Will usually resolve after adolescence
  • Moderate or severe inflammatory disease can scar 
Diagnosis is via examination and is usually very straight forward.

Differential Diagnoses

Acne Rosacea: usually if middle age or later in life. In this disorder the skin not greasy and no comedones


  • Disfiguring
  • Large psycholigcal impact
  • Potential for scarring (which is avoidable)


  • Advice and Reassurance – it is often mild and self-limiting
  • Washing – twice daily with soap and water (any more may be counterproductive)
  • Sunlight – may be beneficial but normal advice regarding sun protection is still important


  • encourage skin peeling
  • reduce inflammation
  • antibiotic effect
  • apply to all affected areas, not just lesions
Benzoyl peroxide      
  • often first line
  • can cause drying and irritation of the skin but persevere
 Topical Abx   
  • Usually clindamycin or erythromycin
  • Given with Benzoyl peroxide to reduce resistance
 Topical retinoids  
  • Reduce inflammation
  • Low systemic absorption but same CIs as oral route (below)
  • may take several months to act
  • allow 4 months to assess effects
  • can be combined with topical treatment
  • Oxytetracycline usually first line
  • Clindamycin and erythromycin also used
  • Probably no greater efficacy than topical benzoyl peroxide/Abx
  • a retinoid, reduces serum secretion
  • effective but limited by toxicity
  • Teratogenic (up to one month after discontinuation)
  • Dry skin, lips and eyes common
  • Probably no link with psychiatric illness
  • only as a last resort
  • oestrogen contraceptive pill is often effective
  • avoid norethisterone containing contraceptives

Related entries