What are the main types of rosacea, particularly in a patient with fair skin and skin symptoms?

Classification of Rosacea

Modern rosacea classification has transitioned from the traditional four-subtype system to a phenotype-based approach that focuses on individual clinical features rather than rigid categories. 1

Historical Subtype Classification (Pre-2017)

The traditional classification system, established in 2002, grouped rosacea into four distinct subtypes: 1

• Erythematotelangiectatic rosacea (ETR): Characterized by facial erythema (both transient and persistent) and telangiectasia 1
• Papulopustular rosacea (PPR): Defined by inflammatory lesions (papules and pustules) 1, 2
• Phymatous rosacea: Marked by phymatous changes including skin thickening and deformation 1, 2
• Ocular rosacea: Involving eye manifestations such as blepharitis, conjunctivitis, and keratitis 3, 2

Critical Limitation of the Subtype System

The major problem with subtype classification is that individual features frequently overlap across multiple subtypes, making it impractical for patient-centered management. 1 A patient may simultaneously present with erythema, telangiectasia, and papules, which would technically span multiple subtypes. 1

Current Phenotype-Based Approach (2017-Present)

The 2017 Global ROSacea COnsensus (ROSCO) panel—representing dermatologists and ophthalmologists from Africa, Asia, Europe, North America, and South America—established a phenotype-based classification that better reflects individual patient presentations. 1

Diagnostic Features (What Actually Diagnoses Rosacea)

Only two features are independently diagnostic: 1, 3

1. Persistent centrofacial erythema with periodic intensification (triggered by specific factors) 1, 3
2. Phymatous changes (thickening of skin from sebaceous gland hyperplasia) 1, 3

Major Phenotypic Features (Present But Not Individually Diagnostic)

These features characterize rosacea but do not diagnose it alone: 1, 3

• Flushing/transient erythema: Assessed by intensity, frequency, duration, area involved, and associated symptoms 3
• Persistent erythema: Evaluated by intensity and extent 3
• Telangiectasia: Characterized by vessel size and extent of involvement 3
• Inflammatory papules and pustules: Measured by number of lesions and extent of facial involvement 3
• Ocular manifestations: Including blepharitis, meibomian gland dysfunction, conjunctivitis, and keratitis 3

Minor Phenotypic Features

Additional features that may be present: 3

• Burning and stinging sensations 3
• Facial edema 3
• Dry sensation 3

Clinical Application for Fair-Skinned Patients

In patients with fair skin (the most common demographic for rosacea), all phenotypic features are readily visible, making diagnosis straightforward when persistent centrofacial erythema with periodic intensification is present. 3, 4 Fair-skinned patients of Northern European heritage have the highest prevalence of rosacea. 4

Important Diagnostic Pitfall

Do not diagnose rosacea based solely on flushing, telangiectasia, or inflammatory lesions—these require the presence of persistent centrofacial erythema or phymatous changes to confirm the diagnosis. 1, 3 This is a critical distinction from the older 2002 criteria where any single primary feature was considered diagnostic. 1

Why the Classification Changed

The phenotype-based approach addresses rosacea treatment in a manner more consistent with each patient's individual experience, as features span multiple traditional subtypes and respond to different therapies. 1, 3 The pathophysiology involves dysregulation of innate and adaptive immune systems, with increased antimicrobial peptides, neuropeptides, and inflammatory mediators that operate beyond subtype boundaries. 1