Author: Reviewed and updated by Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand; Vanessa Ngan, Staff Writer; Clare Morrison, Copy Editor, June 2014.
Rosacea is a chronic rash involving the central face that most often starts between the age of 30 and 60 years. It is common in those with fair skin, blue eyes and Celtic origins. It may be transient, recurrent or persistent and is characterised by its colour, red.
Although once known as acne rosacea, this is incorrect, as it is unrelated to acne.
There are several theories regarding the cause of rosacea, including genetic, environmental, vascular and inflammatory factors. Skin damage due to chronic exposure to ultraviolet radiation plays a part.
The skin's innate immune response appears to be important, as high concentrations of antimicrobial peptides such as cathelicidins have been observed in rosacea.
Matrix metalloproteinases (MMPs) such as collagenase and elastase also appear important in rosacea.
Hair follicle mites (Demodex folliculorum) are sometimes observed within rosacea papules but their role is unclear.
An increased incidence of rosacea has been reported in those who carry the stomach bacterium Helicobacter pylori, but most dermatologists do not believe it to be the cause of rosacea.
Rosacea results in red spots (papules) and sometimes pustules. They are dome-shaped rather than pointed and unlike acne, there are no blackheads, whiteheads or nodules. Rosacea may also result in red areas (erythematotelangiectatic rosacea), scaling (rosacea dermatitis) and swelling (phymatous rosacea).
Characteristics of rosacea
Rosacea may occasionally be confused with or accompanied by other facial rashes.
In most cases, no investigations are required and the diagnosis of rosacea is made clinically. Occasionally a skin biopsy is performed, which shows chronic inflammation and vascular changes. The Global ROSacea COnsensus (ROSCO) Panel recommends classification using diagnostic, major and minor phenotypes. One diagnostic or two major phenotypes are required for diagnosis.
Tetracycline antibiotics including doxycycline and minocycline are commonly used to treat rosacea
Anti-inflammatory effects of antibiotics are under investigation.
Disadvantages of longterm antibiotics include development of bacterial resistance, so low doses that do not have antimicrobial effects are preferable (eg, 40–50 mg doxycycline daily).
When antibiotics are ineffective or poorly tolerated, oral isotretinoin may be very effective. Although isotretinoin is often curative for acne, it may be needed in low dose long-term for rosacea, sometimes for years. It has important side effects and is not suitable for everyone.
Nutraceuticals targeting flushing, facial redness and inflammation may be beneficial.
Certain medications such as clonidine (an alpha2-receptor agonist) and carvedilol (a non-selective beta blockers with some alpha-blocking activity) may reduce the vascular dilatation (widening of blood vessels) that results in flushing. They are generally well tolerated. Side effects may include low blood pressure, gastrointestinal symptoms, dry eyes, blurred vision and low heart rate.
Oral non-steroidal anti-inflammatory agents such as diclofenac may reduce the discomfort and redness of affected skin. Although these are uncommon, serious potential adverse effects to these agents include peptic ulceration, renal toxicity and hypersensitivity reactions.
Persistent telangiectasia can be successfully improved with vascular laser or intense pulsed light treatment. Where these are unavailable, cautery, diathermy (electrosurgery) or sclerotherapy (strong saline injections) may be helpful. Papulopustular rosacea may also improve with laser treatment or radiofrequency.
Rhinophyma can be treated successfully by a dermatologic or plastic surgeon by reshaping the nose surgically or with carbon dioxide laser.
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