Acne Vulgaris
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  • Acne vulgaris (often shortened to “Acne”) is a disorder of the Pilosebaceous Follicles (oil glands)
  • Incredibly common
    • Almost universal in the second decade of life
    • Also affects adults
  • Initially the result of excess sebum production, which is related to androgen (testosterone) levels
  • 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


  • Rare before the age of 10
  • Peaks in teenage years
    • Age 13-14 in girls
    • Age 18-19 in boys
  • May continue into adulthood, after the age of 25 it affects:
    • 15% of women
    • 5% of men


  • 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
  • Associated factors include:
    • PCOS
    • Steroid use
    • Certain skincare products which may increase oil load on the skin – especially heavy make-up use

Diet and acne

  • No clear, proven pattern
  • Some studies show a link, some don’t
  • Possibly – full fat milk might have a slight effect
  • Probably not a huge factor in development and management of acne


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


  • Open comedones (Blackheads)
    • Indicates hyperkeratinisations
    • Usually don’t form cysts
  • Closed comedones (Whiteheads)
    • Obstructed pilosebaceous units
    • Can cause scarring
    • Can lead to cysts
  • Papules (deep)
    • Small, inflammatory and usually raised, red lesions
  • Pustules (more superficial)
  • Nodules
    • Bigger papules
  • Cysts
    • Develop when there is further infection and inflammation due to P. Acnes
    • Usually >5mm size
    • Indicate a strong inflammatory response at a deep dermal level
    • Can be treated with intra-lesion steroids, antibiotics and isotretinoin
  • Atrophic scars
    • Often fill somewhat within the months after a flare-up
    • Can’t really fully assess scarring until the inflammatory phase has completely resolved


  • 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 clinical; via examination and is usually very straight forward.
  • Disfiguring
  • Large psychological impact
  • Potential for scarring (which is avoidable)
  • If cystic acne is present – refer to a dermatologist early to reduce the risk of scarring

Differential Diagnoses

  • Usually if middle age or later in life
  • Skin is not greasy and there are no comedones
  • Typically mainly affects the face – especially the cheeks
  • Usually older patients
  • If the nose is affected – more likely to be rosacea
Peri-orifical dermatitis


Principles of management
  • Unblock the pores – comedolysis
    • Using topical benzoyl peroxide, isotretinoin gel, or adapalene lotion
  • Decrease bacterial load in the sebum
    • Using topical or oral antibiotics
  • Decrease sebaceous gland activity
    • Isotretinoin (orally)
    • Osetrogens (COCP) – females only!
    • Spironolactone  – usually females only too
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
    • Strong family history
    • Signs of scaring
    • Rapid progression


  • Advice and Reassurance – it is often mild and self-limiting
  • Washing – twice daily with soap and water (any more may be counterproductive)
  • Sunlight – can increase the risk of scarring / make scars appear more visible
  • Skin products – avoid the use of oily products. Use cosmetics sparingly
  • 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 individual 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 Antibiotics   
  • 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, or can use separate creams
 Topical retinoids  
  • e.g. adapeline
  • Reduce inflammation
  • Low systemic absorption but same contraindications as oral route (below)
  • Irritating – many patients don’t tolerate it because of the skin irritation
  • Takes at least 12 weeks to be effective
  • Can be used with other agents (e.g. oral antibiotics or oral COC)
  • Comes in combination with benzoyl peroxide as Epiduo
  • May take several months to act
  • Allow 4 months to assess effects
  • Can be combined with topical treatment
  • Useful fro trunkal acne – which is often not responsive to topical agents
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)
  • Useful in trunk acne – where topical agents are often less effective
  • Oestrogen contraceptive pill is often effective (in women only obviously!)
    • Reduce oil load on the skin – reduces sebum production
    • Reduces free testosterone
    • Takes up to 3-6 months to have an effect on acne
    • Cessation of the pill often causes a flare of acne for 3-6 months
    • Avoid norethisterone containing contraceptives
    • e.g. “Brenda 35-ED”
  • Spironolactone
    • Can’t be used in pregnancy
    • 50-100mg daily
    • 30% will cure acne
    • 30% will have good improvement
    • 30% will have mild improvement
    • Can be combined with topical retinoids
    • “Off-label” use

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.


  • Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
  • Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
  • Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy

Read more about our sources

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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