Key Facts

Rosacea is a common facial dermatosis often misdiagnosed as acne. The absence of comedones is the key differentiating feature. Treatment is subtype-directed.

Epidemiology

• UK prevalence: ~5–10% of adults (likely underdiagnosed)
• Peak onset: 30–60 years
• More common in fair-skinned individuals (Fitzpatrick types I–II)
• Female:male ~3:1 for papulopustular; rhinophyma more common in males

Aetiology

• Exact cause unknown; multifactorial
• Demodex folliculorum: increased density in rosacea skin; immune reaction to mite antigens
• Dysregulated innate immunity: cathelicidin (LL-37) overproduction → inflammation, angiogenesis
• Neurovascular dysregulation: TRPV1 receptor activation → flushing, erythema

Pathophysiology

• UV damage → dermal connective tissue disruption and vascular dilation
• Cathelicidin (LL-37) processed by serine protease kallikrein 5 → pro-inflammatory peptides → erythema, papules
• Demodex mites harbour Bacillus oleronius → innate immune activation
• Chronic inflammation → telangiectasia, fibrosis (rhinophyma)

Subtypes

1. Erythematotelangiectatic:

• Persistent centrofacial erythema
• Flushing episodes
• Telangiectasia
• Burning/stinging sensation

2. Papulopustular:

• Papules and pustules on erythematous background
• Centrofacial distribution
• NO comedones (unlike acne)

3. Phymatous:

• Thickened, nodular skin
• Rhinophyma: bulbous, enlarged nose — most recognised
• Can affect chin (gnathophyma), ears (otophyma)

4. Ocular (~50%):

• Blepharitis, conjunctivitis, dry eyes
• Foreign body sensation
• Keratitis (sight-threatening if severe)

Red Flags

• Keratitis (eye pain, photophobia, visual disturbance)
• Rapid progression or unilateral disease (consider SLE, CTCL)
• Granulomatous rosacea (persistent papules without erythema)

Clinical Diagnosis

• Usually clinical; no investigations needed for typical presentation

If Indicated

• Demodex count: skin scraping — increased density (>5/cm²) suggests Demodex-related rosacea
• ANA: if SLE malar rash suspected
• Skin biopsy: rarely needed; perifollicular/perivascular inflammation, Demodex mites, granulomas in granulomatous variant
• Ophthalmology assessment: if ocular symptoms — slit-lamp examination for keratitis

General Measures

• Trigger avoidance: sun protection (SPF 30+), avoid alcohol, spicy food, extremes of temperature
• Gentle skincare: non-soap cleansers, fragrance-free moisturisers
• Sun protection: daily broad-spectrum SPF 30+ (physical sunscreens preferred)

Erythematotelangiectatic

• Brimonidine 0.33% gel OD: topical alpha-agonist; temporary vasoconstriction; beware rebound erythema
• Laser/IPL: for persistent telangiectasia and erythema (specialist)

Papulopustular

• Topical (first-line): ivermectin 1% cream OD (Soolantra) or metronidazole 0.75% gel BD
• Topical alternatives: azelaic acid 15% gel BD
• Oral (moderate-severe): doxycycline 40mg MR OD (Efracea) for 8–16 weeks — anti-inflammatory, not antibiotic dose
• Severe/refractory: oral isotretinoin low dose (0.25–0.5mg/kg/day) — specialist

Phymatous

• Rhinophyma: surgical debulking, CO2 laser, electrosurgery (dermatology/plastics)
• Oral isotretinoin may prevent progression

Ocular

• Lid hygiene: warm compresses, lid scrubs
• Oral doxycycline 40–100mg OD: for moderate-severe
• Ophthalmology referral: if keratitis or visual symptoms

Referral Criteria

• Dermatology: moderate-severe/refractory rosacea, consideration for laser or isotretinoin
• Ophthalmology: ocular rosacea with keratitis or visual symptoms
• Plastics/dermatology: rhinophyma surgical management

• Chronic relapsing condition; no cure but manageable with treatment
• Papulopustular: good response to topical/oral treatment in most
• Ocular rosacea: can cause permanent visual impairment if keratitis untreated
• Rhinophyma: progressive without treatment but responds well to surgery
• QoL impact: significant psychosocial effect (visible facial disease)

Rosacea Subtypes Summary

Rosacea vs Acne