Rosacea is a chronic inflammatory skin disorder that primarily affects the central face and is characterised by persistent or recurrent facial erythema, flushing, visible superficial blood vessels and, in some patients, inflammatory papules and pustules. It is most commonly recognised on the cheeks, nose, chin and central forehead, although the pattern varies between individuals. Rosacea is not simply facial redness and encompasses several overlapping manifestations, including persistent vascular changes, inflammatory lesions, ocular involvement and tissue thickening. The condition often follows a fluctuating course, with periods of relative stability and episodes of exacerbation. It is not contagious and is distinct from acne, allergic reactions and ordinary transient flushing.
The biological mechanisms of rosacea are multifactorial and incompletely understood. Abnormal innate immune activation, neurovascular dysregulation, inflammatory mediators, vascular reactivity and altered responses to environmental stimuli all appear to contribute. The skin barrier can also be impaired, increasing sensitivity to topical products and environmental exposures. Demodex mites, which normally inhabit human pilosebaceous units, are found at increased density in some people with rosacea and may interact with innate immune pathways, but their presence does not mean that rosacea is simply a parasitic infection. Genetic susceptibility, vascular reactivity and environmental factors can influence expression, while no single mechanism adequately explains every clinical phenotype.
Triggers vary substantially among individuals. Commonly reported factors include sunlight, heat, hot drinks, spicy foods, alcohol, emotional stress, vigorous exercise and abrupt temperature changes. These factors generally act as triggers or exacerbating influences rather than being the fundamental cause of rosacea. Ultraviolet radiation can contribute to chronic vascular and inflammatory changes, making photoprotection an important component of management. Some people experience symptoms from multiple triggers, whereas others identify few or none. Keeping track of recurrent exposures can help individualise management, but excessively restrictive avoidance of large numbers of foods or activities is unnecessary when no consistent relationship exists.
Rosacea has several clinical patterns that can overlap within the same person. Erythematotelangiectatic disease is dominated by persistent central facial redness and flushing, while papulopustular disease includes inflammatory lesions that can resemble acne. Phymatous changes involve progressive thickening and enlargement of affected skin, most famously producing rhinophyma when the nose is involved. Ocular rosacea can cause irritation, burning, dryness, redness and eyelid inflammation and, in more significant cases, corneal complications. The presence of comedones strongly favours acne rather than rosacea, while facial scaling, sharply demarcated plaques or a distribution inconsistent with rosacea may suggest another dermatological diagnosis.
Diagnosis is primarily clinical. There is no single laboratory test that confirms rosacea, and investigations are generally used only when another condition needs to be excluded or when the presentation is atypical. A careful history should assess flushing, persistent redness, triggers, ocular symptoms, topical products and medication exposure. Conditions that can mimic rosacea include acne, seborrhoeic dermatitis, lupus erythematosus, contact dermatitis, photodermatoses and steroid-induced facial eruptions. Long-term use of potent topical corticosteroids on the face can itself produce or aggravate rosacea-like changes, illustrating why treatments should not be selected solely on the appearance of redness without considering the underlying diagnosis.
Management combines trigger reduction, skin-care measures and treatments selected according to the dominant phenotype. Gentle cleansing and moisturisation can support the skin barrier, while broad-spectrum sun protection can reduce ultraviolet-related exacerbation. Persistent erythema may be treated with topical agents that reduce vasodilation, and visible telangiectasia can respond to vascular laser or light-based procedures in appropriate specialist settings. Papulopustular disease can be treated with topical anti-inflammatory or antimicrobial agents and, when necessary, systemic therapies such as oral tetracyclines. Treatment of ocular disease may require eyelid care, lubricating drops, systemic therapy or ophthalmological assessment depending on severity. Because rosacea is chronic, treatment often focuses on control rather than permanent elimination.
Rosacea can produce substantial quality-of-life effects because facial changes are visible and can be mistaken for embarrassment, alcohol consumption, sunburn or poor health. Recurrent flushing can itself be socially disruptive, while persistent erythema and phymatous changes can become more difficult to reverse when established. Ocular involvement is clinically important because untreated significant inflammation can affect the ocular surface and, in severe cases, threaten vision. The disease is not caused by poor hygiene, and aggressive cleansing may aggravate sensitive skin. Likewise, rosacea should not automatically be interpreted as an allergy simply because certain foods or environmental conditions provoke flushing.
Rosacea differs from acne principally in its typical vascular component and absence of comedones. It also differs from urticaria because rosacea produces persistent or recurrent changes in defined facial areas rather than transient wheals that disappear within approximately 24 hours. Although rosacea is often described as an adult condition, it can occur outside the typical age range. Prognosis is generally chronic and fluctuating, with treatment capable of reducing symptoms and preventing or controlling complications but not necessarily eliminating the underlying susceptibility. Early recognition is useful because prolonged inflammation, inappropriate steroid use and unaddressed ocular disease can complicate management, while tailored treatment can address vascular, inflammatory, ocular and phymatous manifestations separately.
