What is Rosacea
Rosacea is a chronic inflammatory skin disease that predominantly affects the central facial region, characterized by persistent centrofacial erythema with periodic intensification by trigger factors, or by phymatous changes (skin thickening from sebaceous gland hyperplasia), with either of these two features being independently diagnostic. 1, 2
Core Definition and Pathophysiology
Rosacea results from dysregulation of both innate and adaptive immune systems, with neurovascular abnormalities driving the characteristic centrofacial erythema and inflammatory features. 2 The underlying mechanisms include:
- Immune dysregulation involving CD4+ T lymphocytes, macrophages, mast cells, and dendritic cells forming the inflammatory infiltrate 2
- Elevated inflammatory mediators including antimicrobial peptides, neuropeptides, and nitric oxide radical species that perpetuate inflammation 2, 3
- Trigger factors such as Demodex mites and ultraviolet radiation that activate inflammatory pathways 1, 2, 3
Clinical Presentation
The disease manifests with several key features that can occur independently or in combination:
Diagnostic Features (Either Alone is Sufficient for Diagnosis)
- Persistent centrofacial erythema with periodic intensification by trigger factors (minimum diagnostic feature) 1, 2, 3
- Phymatous changes characterized by skin thickening from sebaceous gland hyperplasia (independently diagnostic) 1, 2, 3
Major Features (NOT Diagnostic Alone)
- Flushing/transient erythema - paroxysmal facial redness lasting typically less than five minutes, often spreading to neck and chest 3, 4, 5
- Inflammatory papules and pustules on an erythematous base without significant scale 2, 3, 5
- Telangiectasia - visible blood vessels assessed by vessel size and extent 3, 5
- Ocular manifestations including blepharitis, conjunctivitis, and keratitis 1, 3, 5
Minor Features
Epidemiology and Demographics
- Affects approximately 16 million people in the United States, with many cases undiagnosed, especially in people with darker skin tones 1, 2
- Peak onset occurs between ages 30-60 years, most commonly in the 40s and 50s 4, 5, 6
- More frequent in women, though men experience the most severe cases 4, 7
- Higher incidence in fair-skinned individuals, particularly those of Northern European descent 4, 8, 7
Diagnostic Challenges
In darker skin types (phototypes V and VI), erythema and telangiectasia may not be visible, requiring greater emphasis on hyperpigmentation and symptoms of irritation such as burning and stinging. 3 The diagnosis remains primarily clinical based on observable characteristics, with each feature evaluated independently to allow for targeted treatment. 1, 2
Clinical Course and Complications
Without treatment, rosacea can lead to significant complications:
- Rhinophyma - severe nasal tissue thickening, predominantly in males 1, 4
- Ocular complications including corneal scarring and neovascularization that can affect both function and appearance 1, 3
- Blepharitis with potential for eyelash loss, eyelid scarring with trichiasis 3
- Significant psychosocial impact affecting quality of life, social and professional interactions due to facial stigmatization 9, 1, 2
Important Clinical Pearls
The current approach has shifted from subtype-based to phenotype-based classification, which addresses rosacea in a manner more consistent with the patient's individual experience and allows for personalized assessment and treatment based on specific manifestations present. 3 This represents a significant advancement from older classification systems that described four subtypes (erythematotelangiectatic, papulopustular, phymatous, and ocular). 4, 5