• Acne vulgaris (often shortened to “Acne”) disorder of the Pilosebaceous Follicles
  • Incredibly common
    • Almost universal in the second decade of life
    • Also affects adults
  • Associated with psychological problems, including depression, anxiety and social phobia
  • Early treatment is associated with better outcome and also reduces the risk of long-term scarring


  • 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 commensal)*
    • *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
  • Without treatment, many cases last up to 10 years


  • Patient often an adolescent
  • Greasy skin
  • Also common in young adults


  • 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
    • Usually >5mm size


  • The face (almost universally)
  • Chest, neck and back (in more severe cases)
  • 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 is not greasy and there are no comedones.


  • Disfiguring
  • Large psychological impact
  • Potential for scarring (which is avoidable)
Defining Severity
  • No universal guidelines
  • Generally considered more severe if:
    • Large numbers of comedones
    • Scarring
    • Resistant to basic treatments
    • Also affecting trunk
    • Having a large psychological impact
  • Consider early referral to dermatologist (and isotretinoin treatment) if worried about severe acne


  • 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
  • By the time most people present to medical services they may have tried basic measures – e.g. benzoyl peroxide is available over the counter (see below)


  • 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
  • Comes in different strengths – start with a low strength (e.g. 2.5%) and increase as required
 Topical Abx
  • Usually clindamycin or erythromycin
  • Using topical antibiotics alone is not recommended as resistance is common
  • Given with benzoyl peroxide to reduce resistance – combination creams are available
 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
Oral Antibiotics 
  • Tetracyclines (e.g., oxytetracycline, doxycycline, minocycline) usually first line
  • Clindamycin and erythromycin also used
  • Probably no greater efficacy than topical a benzoyl peroxide plus antibiotic cream combination
  • Needs to be prescribed by a dermatologist – consider early referral in severe acne
  • A retinoid, reduces serum secretion
  • Very effective (a single 16-week course works in about 80% of cases) but limited by toxicity and side effects
  • Teratogenic (up to one month after discontinuation) – need to be very careful to avoid in pregnancy or patients at risk of pregnancy
  • Dry skin, lips and eyes common
  • Also causes myalgia – particularly related to exercise
  • Rarely can cause a very bad exacerbation of acne
  • Probably no link with psychiatric illness
  • Contraindicated to use with a tetracycline (risk of benign intracranial hypertension) and with the progesterone only pill (reduces its effectiveness and increases the risk of pregnancy)
  • Oestrogen contraceptive pill is often effective (in women only obviously!)
  • Avoid norethisterone containing contraceptives

Consider appropriate management of associated psychological impacts in all patients. Many teenagers will not want to attend school due to acne and it also causes an increase in absence from work in adults. This can harm job prospects.

Having acne is associated with an increased risk of depression and suicide. There is some debate over whether or not isotretinoin (roaccutane) increases suicide risk – this is a hard question to answer as patients have an increased risk anyway – especially those with severe acne – for which isotretinoin is used. There is probably not an increased risk due to the drug.

Related Articles