Many of the factors considered potential causes of rosacea are now coming into sharp focus as a result of medical studies funded by the National Rosacea Society (NRS) research grants program, and the growing body of scientific evidence is making major strides toward defining the precise development of this widespread disorder.
"Thanks to the many thousands of rosacea sufferers who have donated to this program, remarkable progress has been made in understanding this condition despite the challenges presented by its many signs and symptoms," said Dr. Mark Dahl, professor of dermatology at the Mayo Clinic Arizona and a member of the NRS Medical Advisory Board, which selects research grant proposals for funding. He noted that this knowledge is leading the way toward significant advances in treatment and care.
In ongoing research funded by the NRS, Dr. Richard Gallo and colleagues at the University of California-San Diego are continuing to study the role of cathelicidins, which they had discovered may cause inflammatory bumps and pimples as well as vascular effects such as flushing and visible blood vessels called telangiectasia, all primary characteristics of rosacea. Cathelicidins are an anti-microbial molecule that the body produces as part of its immune system to combat illness, and were found to be both more abundant as well as in a different form in rosacea patients, according to their study results published in the prestigious scientific journal Nature Medicine.1
Investigators believe this protective process may be further linked to rosacea because cathelicidins and related biochemicals may be prompted by a variety of factors that also provoke rosacea flare-ups. These factors may include heat, corticosteroids, exposure to the sun's ultraviolet light and microorganisms such as Demodex folliculorum.
In further NRS-funded research, the role of kallikreins -- enzymes also involved in immune response -- is now being studied in rosacea by Dr. Joseph Rothnagel and colleagues at the University of Queensland, Australia. In addition, Dr. Curdin Conrad and colleagues at MD Anderson Cancer Center are now investigating whether interferon and other substances may be present in the development of the disorder.
Studies have also found that the neurovascular system may play a role in the development of rosacea, as demonstrated in NRS-funded research by Dr. Martin Steinhoff, University of Muenster, and colleagues. Dr. Steinhoff's team recently found that neuropeptide-positive sensory nerves around blood vessels, which may be linked to stinging, increase during rosacea's development, and that the balance between several neuropeptides, corresponding receptors and related substances is disrupted in rosacea skin. Additional research is ongoing to determine whether this ineffective interaction contributes to the development of the flushing and inflammation of rosacea.
While Demodex folliculorum -- a microscopic mite that normally inhabits human skin -- has been found in greater numbers in those with rosacea, it has been long debated whether it may be a cause or simply a result of rosacea. It now appears that its true connection with rosacea's signs and symptoms may be linked to a distinct bacterium associated with the mites, called Bacillus oleronius. In a study funded by the NRS, Dr. Kevin Kavanagh and colleagues at the National University of Ireland-Maynooth found that B. oleronius stimulated an inflammatory response in 79 percent of study patients with subtype 2 (papulopustular) rosacea.
In other new studies funded by NRS research grants, Dr. Thad Wilson and colleagues at Ohio University are investigating how flare-up triggers may stimulate nerve activity in the skin, and Dr. Jamison Feramisco and colleagues at the University of California-San Francisco are testing for possible genetic components of the disorder. Dr. Noreen Lacey and colleagues at the University College Dublin Clinical Research Centre are evaluating the effect of topical antibiotics on lipid production and other properties that may be involved in rosacea.
In a recently completed study, Dr. Robert Walters and colleagues at Duke University identified the molecular pathway for flushing caused by niacin, also known as vitamin B3 or nicotinic acid.
- Yamasaki K, DiNardo A, Bardan A, et al. Increased serine protease activity and cathelicidins promotes skin inflammation in rosacea. Nature Medicine 2007;13:975-980.