Although rosacea today can be controlled with long-term therapy, a cure has yet to be found and its cause is still unknown. Fortunately, growing interest among medical researchers now offers hope that the approximately 13 million Americans who suffer from rosacea will reap the benefits of new scientific insights into this embarrassing and potentially disfiguring disease.
"Perhaps nowhere else in dermatology is so little known about a condition that affects so many," said Dr. Jonathan Wilkin, director of Dermatologic and Dental Drug Products at the U.S. Food and Drug Administration and chairman of the medical advisory board for the National Rosacea Society's new research grants program. "Theories about its origins abound, and increased research funding should result in more studies to better define the best approaches for its treatment, control or prevention."
Rosacea is now widely considered a vascular disorder because of the hallmarks of frequent flushing and facial redness that plague its victims. However, the root cause or causes of this flushing are uncertain, and it may result from numerous factors.
Some doctors have recently speculated that the flushing associated with rosacea might be prompted by a defect in the nervous system. Supporting this theory is the observation that the worst rosacea outbreaks may occur when patients are under emotional stress, according to Dr. Neil Shear, director of Clinical Pharmacology and deputy director of Dermatology at the University of Toronto Medical School.
The increased blood flow during flushing may also lead to swelling, some experts have noted. If the dilated blood vessels become "leaky," extra fluid may accumulate in the tissues faster than the lymphatic system can remove it. In addition, the immune response often triggered by inflammation may result in a thinning of the skin, causing tiny blood vessels to become more prominent and visible.
Beyond vascular factors, various external causes have been considered potential contributors to rosacea. In the past, the bacterium Helicobacter pylori, which plays a role in duodenal ulcers, was believed to be potentially implicated in rosacea -- possibly by raising gastrin levels that may stimulate flushing. However, a recent study of 204 patients found that the prevalence of H. pylori is similar in patients with rosacea and in those without the disorder.1 Another recent study also found no significant difference in H. pylori between the two groups, but noted that the rosacea patients complain significantly more often of "indigestion" and use more antacids unrelated to H. pylori infection.2
Another potential external cause of rosacea is Demodex folliculorum, a microscopic mite that is a normal inhabitant of human skin. Some studies have found that Demodex exist in greater numbers in rosacea patients than in people without rosacea. However, experts have noted that it is unclear whether the number of mites is a cause or a result of rosacea. They alternately suggest the possibility that the Demodex mites can stimulate an inflammatory reaction, or that the mites may simply find the lesions of rosacea an attractive home.
The National Rosacea Society's research grants program will provide funding for important scientific research on the potential causes and other key aspects of this poorly understood disorder. Awarding of grants and study results will appear in future issues of Rosacea Review. Readers can support this new program by sending a tax-deductible donation along with the donation form to the National Rosacea Society, 111 Lions Dr., Ste. 216, Barrington, Illinois 60010.
Jones MP, Knable AL Jr., White MJ, Durning SJ: Helicobacter pylori in rosacea: Lack of an association. Archives of Dermatology. 1998;134:511.
Sharma VK, Lynn A, Kaminski M, Vasudeva R, Howden CW: A study of the prevalence of Helicobacter pylori infection and other markers of upper gastrointestinal tract disease in patients with rosacea. American Journal of Gastroenterology. 1998;93:220-222