Dermatology Made Easy is based on the most popular topics from DermNet NZ's vast array of material. The book combines the essential focus of the ‘Made Easy’ book series with the authority and knowledge base of DermNet NZ's unparalleled resources.
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 affects those aged 30 to 60. 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. Cathelicidins are part of the skin's normal defence against microbes.
Cathelicidins promote infiltration of neutrophils in the dermis and dilation of blood vessels. Neutrophils release nitric acid also promoting vasodilation. Fluid leaks out of these dilated blood vessels causing swelling (oedema); and proinflammatory cytokines leak into the dermis, increasing the inflammation.
Matrix metalloproteinases (MMPs) such as collagenase and elastase also appear important in rosacea. These enzymes remodel normal tissue and help in wound healing and production of blood vessels (angiogenesis). But in rosacea, they are in high concentration and may contribute to cutaneous inflammation and thickened, hardened skin. MMPs may also activate cathelicidins contributing to inflammation.
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 may be aggravated by facial creams or oils, and especially by topical steroids.
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, scaling (rosacea dermatitis) and swelling.
Characteristics of rosacea include:
Rosacea may occasionally be confused with or accompanied by other facial rashes including:
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.
Tetracycline antibiotics including doxycycline and minocycline reduce inflammation. They reduce the redness, papules, pustules and eye symptoms of rosacea. The antibiotics are usually prescribed for 6 to 12 weeks, with the duration and dose depending on the severity of the rosacea. Further courses are often needed from time to time, as the antibiotics don't cure the disorder.
Anti-inflammatory effects of antibiotics are under investigation. They have been shown to inhibit MMP function and in turn reduce cathelicidins and inflammation. The effective dose of tetracyclines in rosacea is lower than that required to kill bacteria, so they are not working through their antimicrobial function.
Disadvantages of longterm antibiotics include development of bacterial resistance, so low doses (eg 40-50mg doxycycline daily) that do not have antimicrobial effects are preferable.
Metronidazole cream or gel can be used intermittently or long-term on its own for mild inflammatory rosacea and in combination with oral antibiotics for more severe cases.
Azelaic acid cream or lotion is also effective for mild inflammatory rosacea, applied twice daily to affected areas.
Facial redness can be treated by brimonidine gel, an alpha-2 adrenergic agonist. A new product, oxymetazoline hydrochloride cream, an alpha1A adrenoceptor agonist, was approved by FDA in January 2017 and is expected to be marketed in May 2017.
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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