Acneiform Eruptions

Overview – Acneiform Eruptions

Acneiform eruptions are a group of papulopustular skin conditions that resemble acne but vary in cause, distribution, and treatment. Acne vulgaris is the most common, particularly in adolescents, whereas rosacea affects older adults and lacks comedones. Differentiating between these disorders is essential for appropriate treatment and patient reassurance. This article covers the causes, clinical features, and management of key acneiform eruptions.

Acne Vulgaris (Common Acne)

Aetiology & Pathogenesis

• Strong genetic predisposition
• Involves chronic inflammation of the pilosebaceous unit
• Pathogenic mechanisms include:
  • Duct blockage from excess keratin at follicular openings
  • Increased sebum production (androgen-mediated)
  • Overgrowth of Cutibacterium (Propionibacterium) acnes
  • Rupture of sebaceous duct → inflammation and possible scarring
• Combined oral contraceptives with progesterone may exacerbate acne

Epidemiology

• Common in teenagers, though may occur at any age
• Often more severe in males

Clinical Features

• Lesions on face, upper chest, and back
• Varies in severity:
  • Comedones (open = blackheads, closed = whiteheads)
  • Papules & pustules
  • Severe cases → nodules, cysts, and scarring

Diagnosis

• Acne triad: papules + pustules + comedones
• Key differential: Rosacea

Treatment

• Topical agents:
  • Benzoyl peroxide (antiseptic)
  • Retinoids (e.g. tretinoin)
  • Keratolytics (e.g. salicylic acid)
• Oral therapy (for moderate–severe acne):
  • Tetracycline antibiotics (also anti-inflammatory)
  • Isotretinoin (for nodulocystic acne)
• Hormonal therapy (e.g. COCPs) in some females
• Treat aggressively early to avoid scarring

Prognosis

• Typically self-limiting
• Safe and effective treatments available
• Scarring is preventable with timely intervention

Rosacea

What is It?

• Chronic inflammatory facial disorder
• Presents with papules and pustules, but no comedones
• Occurs mainly in middle-aged adults (30–50 years)

Aetiology

• Unknown cause
• Familial association suspected
• Triggered by:
  • Heat, steam, hot/spicy foods
  • Alcohol
  • Stress
  • Sunlight

Clinical Features

• Predominantly affects the face
• Early signs: flushing, burning, stinging
• Distinguishing signs:
  • Persistent facial erythema
  • Telangiectasia (dilated capillaries)
  • Papules and pustules, but NO comedones
• Severe cases:
  • Rhinophyma (bulbous nose)
  • Facial oedema
• Does not cause scarring
• Can have a significant psychosocial impact

Diagnosis

• Differentials include:
  • Acne (has comedones)
  • Lupus (malar rash without pustules)
  • Sun damage
  • Menopause (flushing)

Treatment

• Avoid triggers (diet, environment)
• Topical and oral antibiotics (anti-inflammatory effect)
• Retinoids
• Laser therapy for telangiectasia and persistent erythema
• Avoid corticosteroids – worsen rosacea and may cause perioral dermatitis

Summary – Acneiform Eruptions

Acneiform eruptions include acne vulgaris and rosacea, both of which present with inflammatory skin lesions but differ in pathophysiology and treatment. Acne presents with comedones and often resolves in adolescence, while rosacea is a chronic adult condition without comedones. Recognising the features of acneiform eruptions allows for accurate diagnosis, early treatment, and prevention of complications like scarring. For a broader context, see our Skin & Dermatology Overview page.