Literature review highlights renewed interest in rosacea research

Research interest in rosacea has entered a renaissance.

Dr. Powell, consultant dermatologist, Mater Hospital, Dublin, Ireland, suggests that several factors seem to be fueling the activity in rosacea research.

Several papers on epidemiology have been published recently and their results include some findings that are consistent with existing concepts. However, they also contain some conflicting data about prevalence.

In agreement with some previous reports, a Greek study of 615 patients showed that males and females were equally effected, although males had a later age of onset than females, 59 years vs. 48 years. In addition, that study reported rosacea was associated with significant seasonal variation in which the disease was most severe in the winter and spring. Also as expected, erythematotelangiectatic rosacea (ETR) was found to be the most common variant,effecting 72 percent of the patients, and rhinophyma effected males more often than females.

Data on prevalence are available from two recent studies. One conducted in the Faroe Islands reported a prevalence of 0.09 percent, whereas a Swedish study found the prevalence of rosacea was much higher at about 10 percent.

Prompted to undertake his own study, Dr. Powell and colleagues are examining 1,000 randomly selected persons in Ireland, including 500 indoor workers and 500 outdoor workers, and will be assessing evidence of photodamage and its possible relationship to rosacea. So far, the investigation of the indoor workers has been completed, and the prevalence rate of rosacea in that subgroup is 2.9 percent.

"That rate is more consistent with data from another study out of Australia. Surprisingly and somewhat disappointingly, we have not seen a relationship between rosacea and photodamage, although we have found photodamage is associated with flushing, erythema and telangiectasia," he reports.

That latter finding raises the point that there continues to be debate on how to define ETR and how to differentiate it from actinic damage.

"Perhaps the prevalence data are being skewed by difficulty in recognizing the ETR variant of rosacea so that results of studies reporting a higher rate reflect inclusion of patients who simply have actinic damage without rosacea," he tells Dermatology Times.

CLINICAL ADVANCES In the area of rosacea treatment, the approval of subantimicrobial dose doxycycline for the treatment of rosacea stands out as a major recent development.

However, Dr. Powell also highlights several other clinical studies of rosacea treatment.

In a small study published last year, Craige and colleagues reported good results using propranolol for symptomatic treatment of rosacea-associated cutaneous flushing. Patients were started on a dose of 40 mg per day that was gradually increased.

"It was encouraging to see some pharmacotherapy identified that could help control flushing. Notably, patients with rosacea may develop a vicious circle involving anxiety and flushing, and part of the mechanism of action of propranolol may involve its anxiolytic property," Dr. Powell says.

A study published by Altinyazar et al. reported that adapalene gel was as effective as metronidazole gel for reducing the number of inflammatory lesions in rosacea patients. However, metronidazole gel was more effective for improving erythema.

Also noteworthy was a brief report appearing in the Australian Journal of Dermatology describing a patient who was treated with kilovoltage photon radiotherapy for a basal cell carcinoma on the nose and who simultaneously benefited with improvement of rhinophyma.

DEFINING THE CLINICAL SPECTRUM Several recent papers further the debate on the clinical spectrum of rosacea and subtype classification.