Acne vulgaris
Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit producing comedones, papules, pustules, and in severe disease nodules and scarring on the face, chest, and back. First-line treatment is a topical retinoid, escalating through topical or oral antibiotics paired with benzoyl peroxide, hormonal therapy, or oral isotretinoin as severity and scarring dictate.
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What this article covers
- Overview
A chronic inflammatory disorder of the pilosebaceous unit triggered by follicular colonization with Cutibacterium acnes, abnormal keratin turnover, increased sebum, and subsequent inflammation.
- Epidemiology
A common disorder encountered across primary care and dermatology, presenting with papules and pustules on the face, chest, and back.
- Risk factors
Follicular keratin plugging and abnormal keratinocyte turnover, the initiating step in comedone formation.
- Pathophysiology
Follicular hyperkeratinization plugs the pilosebaceous unit, forming the microcomedone, the precursor lesion to all subsequent acne lesions.
- Clinical features
Open comedones (blackheads) and closed comedones (whiteheads) are the defining primary lesions; their presence establishes the diagnosis.
- Differential diagnosis
Periorificial dermatitis: clustered erythematous papules and pustules around the mouth, nose, or eyes without comedones, unlike acne where comedones support the diagnosis.
- Diagnosis
This is a clinical diagnosis established by lesion recognition: the presence of comedones, open or closed, supports the diagnosis, together with inflammatory papules and pustules in the classic…
- Management
First-line for all forms of acne is a topical retinoid (for example adapalene 0.3% gel, apply a thin film to the entire affected area once daily in the evening, reassessing if there is no response…
- Complications
Permanent scarring from unresolved inflammatory nodules and cysts, the principal long-term morbidity of undertreated severe acne.
- Prognosis
Most acne responds to stepwise topical and, when needed, systemic therapy, with lesion clearance expected over weeks to months on an appropriate regimen.
- Prevention
Early initiation of a topical retinoid at the first sign of comedonal acne to prevent progression to inflammatory and scarring disease.
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