Acne

• Pathophysiology:

  • Chronic inflammation with or without localised infection in pockets of the skin - pilosebaceous unit
  • Pilosebaceous units contain hair follicles and sebaceous glands - produce sebum
  • Acne results from increased production of sebum - trapping of keratin and blockage of the pilosebaceous unit
  • Androgenic hormones increase secretion of sebum
• The Propionibacterium acnes bacteria is felt to play an important role in acne. This is a bacteria that colonises the skin. It is thought that excessive growth of this bacteria can exacerbate acne. 
• Swollen and inflamed units are called comedones.
• Presentation:

  • Macules are flat marks on the skin
  • Papules are small lumps on the skin
  • Pustules are small lumps containing yellow pus
  • Comedomes are skin coloured papules representing blocked pilosebaceous units
  • Blackheads are open comedones with black pigmentation in the centre
  • Ice pick scars are small indentations in the skin that remain after acne lesions heal
  • Hypertrophic scars are small lumps in the skin that remain after acne lesions heal
  • Rolling scars are irregular wave-like irregularities of the skin that remain after acne lesions heal
• Management:

  • Topical benzoyl peroxide - reduces inflammation and toxic to P. acnes bacteria
  • Topical retinoids - slow production of sebum
  • Topical antibiotics such as clindamycin
  • Oral antibiotics such a lymecycline
  • Oral contraceptive pill - slow production of sebum
• Oral retinoids for severe acne (i.e. isotretinoin) is an effective last-line option, although it is only prescribed by a specialist after other methods fail. This needs careful follow-up and monitoring and reliable contraception in females. Retinoids are highly teratogenic.
• Oral isotretinoin (Roaccutane):

  • Retinoid
  • Strongly teratogenic
  • Dry skin and lips
  • Photosensitivity of skin
  • Depression, anxiety, aggression and suicidal ideation
  • Rarely stevens-johnson syndrome and toxic epidermal necrolysis
• Presentation can vary:

  • Mild - predominantly non-inflamed lesions (open and closed comedones) with few inflammatory lesions
  • Moderate - more widespread with an increased number of inflammatory papules and pustules
  • Severe - widespread inflammatory papules, pustules and nodules or cysts. Scarring may be present
• Open comedone = blackhead

  Closed comedone = whitehead
• Papules and pustules are comedones that have become inflamed
• Take a history asking about:

  • Duration, type and distribution of lesions
  • Previous treatment (including OTC) and response
  • Exacerbating factors - menstruation, contraceptive, cosmetics
  • Systemic features - acne fulminans can present with fever, arthralgia and myalgia
  • Psychosocial impact
  • Family history - endocrine disorders, PCOS, acne and other skin conditions
  • Drug history - some meds can cause or exacerbate acne
  • Hyperandrogenism - irregular periods, androgenic alopecia or hirsutism in women
• Drugs that can cause or exacerbate acne:

  • Androgens (testosterone)
  • Corticosteroids
  • Isoniazid
  • Ciclosporin
  • Lithium
• Exam:

  • Look for clinical features of acne: non-inflammatory comedones and inflammatory papules, pustules, nodules and scarring
  • Comedones must be present for a diagnosis of acne
  • Look for signs of other disorders that can present with acne such as hyperandrogenism or PCOS
• Investigations:

  • Most people with acne do not require any investigations
  • Consider investigations/referral to endocrinology for people presenting with clinical features of PCOS/hyperandrogenism
• Give the person clear information:

  • Topical retinoids and oral tetracyclines are contraindicated during pregnancy and when planning a pregnancy
  • Importance of adhering to treatment as positive effects can take 6-8 weeks (skin cycle)
  • Not to over cleanse
  • Use non-comedogenic skin care/make up
  • Persistent picking can increase risk of scarring
  • Treatments may irritate the skin, especially at the start of treatment
• Mild and moderate acne may be sufficiently controlled with topical therapies:

  • Without prescription - salicylic acid (keratolytic that unblocks pores), benzoyl peroxide (antibacterial effects)
  • Prescription - Combination of topical benzoyl peroxide with adapalene (retinoid) or topical clindamycin
• Treatment length:

  • 12 weeks
  • Treatment usually applied once daily in the evening
  • Review after treatment finished
• Moderate to severe management:

  • Stronger dose topical treatments
  • Can add oral antibiotic - doxycycline or lymecycline
  • Combined oral contraceptives + topical agents
  • Spironolactone (women) - anti-androgen
  • Systemic retinoid
• Do not use the following to treat acne: 

  • Monotherapy with a topical antibiotic.
  • Monotherapy with an oral antibiotic.
  • A combination of a topical antibiotic and an oral antibiotic.
• When to refer:

  • Same day urgent if acne fulminans
  • Nodulo-cystic acne
  • Not responded to 2 completed courses of treatment (mild)
  • Moderate to severe acne not responded to treatment that includes oral antibiotic
  • Persistent psychological distress
• Antibiotics can only be given for a maximum of 6 months