Study finds cause of rosacea


BACTERIA ARE to blame for the inflammatory skin condition rosacea, according to a study involving Irish scientists.

The discovery should pave the way to faster diagnosis and more streamlined treatments for the disorder.

Rosacea affects around three per cent of the population and manifests as red, inflamed skin which, in severe cases, can affect a patient’s confidence, explained researcher Dr Kevin Kavanagh, a senior lecturer in biology at NUI Maynooth.

The cause of the condition has been unclear, but tiny Demodex mites in facial skin pores have been suspects.

“On average, an adult without rosacea will have one mite per square centimetre, but in people with rosacea, that increases up to 20 per square centimetre,” said Dr Kavanagh.

Meanwhile, antibiotics can lessen symptoms, but no-one has known why, he added. “So we started to ask a few years ago why anti-bacterials work when there was no apparent role for bacteria.”

Working with the Mater hospital, the researchers previously identified a Bacillus bacterium inside Demodex mites. The bacteria release two proteins that trigger an inflammation in patients with facial rosacea.

The NUIM researchers then teamed up with US doctor Scheffer Tseng and found a similar link between the bacteria and ocular rosacea, which occurs around the eyes.

Immune tests on 30 patients found that 80 per cent had been exposed to large amounts of the two bacterial proteins, said Dr Kavanagh of the study, which is to be published in Ophthalmology later this year.

“Now that we know it’s primarily probably a bacterial disease, we know the proper way to treat it is with antibiotics at a low level over a long period of time,” Dr Kavanagh said, noting that washing the skin with dilute tea tree oil also killed the bacteria.

“The other implication is that we could do a simple blood test to say whether a patient has rosacea or not. That’s something we will investigate in the future.”