5.3 Acne Vulgaris, Rosacea & Perioral Dermatitis
Key Takeaways
- European acne guidance favours fixed combinations such as adapalene with benzoyl peroxide for papulopustular acne and oral isotretinoin for severe nodular or conglobate acne.
- Oral antibiotics for acne should be combined with a topical retinoid or benzoyl peroxide and limited to about 3 months to reduce antimicrobial resistance.
- Acne fulminans presents with painful ulcerating nodules and often fever, can be triggered by starting isotretinoin, and is treated with oral prednisolone and reduced or paused isotretinoin.
- The ROSCO rosacea panel defines two diagnostic phenotypes, fixed centrofacial erythema with periodic intensification and phymatous change, and treats each feature separately.
- Perioral dermatitis is strongly linked to topical corticosteroid use and is treated by stopping the steroid, with topical metronidazole or an oral tetracycline if needed.
5.3 Acne Vulgaris, Rosacea & Perioral Dermatitis
These three conditions dominate facial dermatology. Questions often test the choice of first-line treatment, how to use antibiotics responsibly, and recognition of severe variants that need urgent systemic therapy.
Acne Vulgaris
Pathogenesis
Acne is a disease of the pilosebaceous unit with four main factors:
- Increased sebum production driven by androgens (including local conversion by 5-alpha-reductase).
- Follicular hyperkeratinisation, forming the microcomedo and then open (black) and closed (white) comedones.
- Colonisation by Cutibacterium acnes (formerly Propionibacterium acnes), which activates innate immunity through Toll-like receptor 2.
- Inflammation, with IL-1 and other cytokines, producing papules, pustules, and nodules.
Diet (high glycaemic load and possibly dairy), and insulin-like growth factor 1 may contribute.
Clinical Forms and Variants
| Form | Features |
|---|---|
| Comedonal | Open and closed comedones, little inflammation |
| Papulopustular | Inflammatory papules and pustules, mild to moderate |
| Nodular / conglobate | Deep nodules, sinus tracts, scarring; acne conglobata is the most severe chronic form |
| Acne fulminans | Sudden painful ulcerating and haemorrhagic nodules, often with fever, arthralgia, and raised inflammatory markers; can follow the start of isotretinoin |
| Neonatal (cephalic pustulosis) | Papulopustules in the first weeks, linked to Malassezia; self-limiting |
| Infantile acne | From 3 to 6 months; persistent or severe disease should prompt a check for hyperandrogenism |
| Drug-induced | Monomorphic papulopustules without comedones: corticosteroids, androgens and anabolic steroids, lithium, isoniazid, halogens, EGFR inhibitors |
| Hormonal | Adult women with lower-face acne; look for polycystic ovary syndrome (hirsutism, irregular periods) |
| Chloracne | Comedones and cysts behind the ears and on the malar area after halogenated aromatic hydrocarbon (dioxin) exposure |
| Acne excoriée | Picked lesions, often in young women; psychological factors |
European Treatment Recommendations
European evidence-based guidance (EDF/EuroGuiDerm) grades treatment by acne type and severity:
| Acne Type | First-Choice Options |
|---|---|
| Comedonal | Topical retinoid (adapalene, tretinoin) or azelaic acid |
| Mild-to-moderate papulopustular | Fixed combination adapalene + benzoyl peroxide or clindamycin + benzoyl peroxide; azelaic acid |
| Severe papulopustular / moderate nodular | Oral isotretinoin, or an oral tetracycline (doxycycline, lymecycline) combined with adapalene or adapalene + benzoyl peroxide |
| Severe nodular / conglobate | Oral isotretinoin; if not possible, oral antibiotic plus topical combination |
Antibiotic stewardship:
- Do not use topical or oral antibiotics alone. Always combine them with benzoyl peroxide or a topical retinoid, which reduces resistance.
- Limit oral antibiotic courses to about 3 months, then maintain with a topical retinoid.
- Avoid using topical and oral antibiotics together.
Hormonal therapy: combined oral contraceptives can help women with acne. Those containing cyproterone acetate with ethinylestradiol are restricted in the EU to moderate-to-severe acne (and hirsutism) after topical treatment or antibiotics have failed, because of venous thromboembolism risk. Spironolactone is used off-label.
Isotretinoin reduces sebum, normalises keratinisation, and indirectly reduces C. acnes. Its dosing, monitoring, and EU Pregnancy Prevention Programme are covered in the oral retinoid section. For acne fulminans, start or continue oral prednisolone (about 0.5–1 mg/kg), pause or reduce isotretinoin, and reintroduce it at a low dose under steroid cover.
Scarring: atrophic (ice-pick, boxcar, rolling) and hypertrophic or keloid scars. Treat the acne early to prevent them. Established scars can be treated with lasers, chemical peels, microneedling, subcision, or fillers.
Rosacea
Rosacea is a chronic inflammatory disease of the central face, most often in fair-skinned adults. Triggers include heat, sunlight, alcohol, hot drinks, spicy food, and exercise. Neurovascular dysregulation, innate immune activation (cathelicidin), and Demodex mites are involved.
ROSCO Phenotype Approach
The global ROSacea COnsensus (ROSCO) panel replaced the older subtypes with phenotypes, each treated on its own merits:
| Category | Features |
|---|---|
| Diagnostic (one is enough) | Fixed centrofacial erythema with periodic intensification; phymatous changes (for example rhinophyma) |
| Major (two or more suggest rosacea) | Flushing or transient erythema; inflammatory papules and pustules; telangiectasia; ocular signs (lid margin telangiectasia, blepharitis, keratitis) |
| Minor | Burning, stinging, oedema, dryness |
Treatment by Feature
- Persistent erythema: brimonidine gel (alpha-2 agonist) or oxymetazoline cream; vascular lasers and intense pulsed light.
- Papules and pustules: ivermectin 1% cream, metronidazole, azelaic acid; for moderate-to-severe disease, oral doxycycline 40 mg modified-release (anti-inflammatory dose); low-dose isotretinoin (off-label) for refractory disease.
- Telangiectasia: vascular laser (pulsed dye, KTP) or intense pulsed light.
- Phyma: surgery, ablative laser, or electrosurgery; isotretinoin for early disease.
- Ocular rosacea: lid hygiene and warm compresses, topical or oral doxycycline, and ophthalmology referral for keratitis.
- General: gentle skincare, daily sun protection, and trigger avoidance.
Differentials: lupus erythematosus (no pustules, photosensitive), seborrhoeic dermatitis, acne (comedones), carcinoid flushing, and steroid-induced rosacea after facial corticosteroid use.
Perioral (Periorificial) Dermatitis
- Who: mainly young women, also children.
- Clinical: small red papules and pustules around the mouth, nose, and sometimes the eyes, with a clear rim of spared skin next to the lip vermilion.
- Cause: strongly associated with topical corticosteroid use, also heavy cosmetics and fluoridated toothpaste.
- Treatment: stop the topical steroid ("zero therapy"). Warn about a rebound flare. Use topical metronidazole, erythromycin, azelaic acid, or pimecrolimus; for extensive disease, an oral tetracycline for 6–8 weeks (erythromycin in young children).
- Granulomatous periorificial dermatitis in children (including facial Afro-Caribbean childhood eruption) produces yellow-brown papules with granulomas on histology.
A 17-year-old boy has moderate papulopustular facial acne and is started on oral doxycycline. Which accompanying plan follows European acne guidance?
Three weeks after starting isotretinoin, an 18-year-old develops fever, joint pain, and painful ulcerating haemorrhagic nodules on the chest and back. What is the most appropriate management?
According to the ROSCO panel, which single finding is enough on its own to diagnose rosacea?
A 28-year-old woman has used a potent steroid cream on her face for 2 months. She now has small papules and pustules around her mouth and nose, with a narrow rim of normal skin next to the lip. What is the key first step in management?