Acne vulgaris

Acne vulgaris is a common condition, which affects most people at some point in their lives (1).

Acne vulgaris is a common, chronic, inflammatory disease of the pilosebaceous unit.

This is a polymorphic eruption primarily of the face, which usually occurs in adolescents during puberty. It also occurs on the upper trunk and neck. It is characterised by the obstruction of the pilosebaceous follicle with keratin plugs. This results in comedones (the primary non inflammatory lesions), inflammation and pustules.

• nearly 90% of teenagers suffer from acne, and half of them will continue to experience symptoms as adults (2)
  • peak incidence is 13-16 years, although it may continue into the 20's, 30's and later
  • females with polycystic ovary syndrome or those with excess cortisol (e.g. steroid use) are prone
• by age 40 years, 1% of men and 5% of women still have lesions (2)
• acne has clear detrimental effects on a psychosocial level and can lead to permanent scarring
• a common presenting complaint in primary care, accounting for more than 3.5 million annual visits to General Practitioners in the UK (3)

The condition may be triggered by an over-responsiveness of the sebaceous glands to the effects of androgenic hormones which results in an increase in sebum production (4). The anaerobic bacterium, Propionobacterium acnes has an uncertain role. It may colonize the comedones, resulting in inflammation (5).

Occurrence before the onset of puberty requires further investigation to exclude underlying adrenal pathology.

Acne vulgaris can be broadly categorized into:

• mild
• moderate
• severe

Click here for an example image of this condition

Differential diagnoses include rosacea, folliculitis, angiofibromas, perioral dermatitis, and keratosis pilaris.

Management principles

• NICE suggest people with acne a 12-week course of 1 of the following first-line treatment options, taking account of the severity of their acne and the person's preferences, and after a discussion of the advantages and disadvantages of each option: (6)
  • a fixed combination of topical adapalene with topical benzoyl peroxide for any acne severity
  • a fixed combination of topical tretinoin with topical clindamycin for any acne severity
  • a fixed combination of topical benzoyl peroxide with topical clindamycin for mild to moderate acne
  • a fixed combination of topical adapalene with topical benzoyl peroxide, together with either oral lymecycline or oral doxycycline for moderate to severe acne
  • topical azelaic acid with either oral lymecycline or oral doxycycline for moderate to severe acne.
• a network meta-analysis concluded that (7):
  • oral isotretinoin is the most effective acne treatment, followed by combination therapy consisting of an oral or topical antibiotic with topical retinoid and benzoyl peroxide (BPO)
  • for monotherapies, oral and topical antibiotics and topical retinoids have comparable efficacy for inflammatory lesions, while oral and topical antibiotics are less effective for noninflammatory lesions and should not be used as monotherapy due to the risk of bacterial resistance developing
  • most guidelines suggest that duration of oral antibiotics for acne should be limited to 3 months, although National Institute for Health and Care Excellence suggests up to 6 months
  • hormonal treatments, such as the combined contraceptive pill, are an alternative treatment for women - however, the use of hormonal treatments can take 3–6 months to work
  • is growing evidence for use of spironolactone in women with persistent acne (off-label use at present) - however, this is likely to take 3–6 months to work.

References:

1. Hay RJ, Johns NE, Williams HC, et al. The global burden of skin disease in 2010: an analysis of the prevalence and impact of skin conditions. J Invest Dermatol. 2014 Jun;134(6):1527-34.

2. Collier CN, Harper JC, Cafardi JA, et al. The prevalence of acne in adults 20 years and older. J Am Acad Dermatol. 2008;58(1):56–59.

3. Dawson, A.L. and Dellavalle, R.P. (2013) Acne vulgaris. BMJ 346, f2634.

4. Bhate K, Williams HC. Epidemiology of acne vulgaris. Br J Dermatol. 2013 Mar;168(3):474-85.

5. Corvec S, Dagnelie MA, Khammari A, et al. Taxonomy and phylogeny of cutibacterium (formerly propionibacterium) acnes in inflammatory skin diseases. Ann Dermatol Venereol. 2019 Jan;146(1):26-30.

6. Acne vulgaris: management. NICE guideline [NG198] Published: 25 June 2021 Last updated: 07 December 2023

7. Chung-Yen H et al. Comparative Efficacy of Pharmacological Treatments for Acne Vulgaris: A Network Meta-Analysis of 221 Randomized Controlled Trials. Annals of Family Medicine Jul 2023, 21 (4) 358-369; DOI: 10.1370/afm.2995