From exposure to heat to cigarette smoking, new studies are tracing the effects of rosacea triggers in the search for the cause or causes of this widespread, often life-disruptive disorder.

In interim results of a new study funded by the National Rosacea Society, Dr. Kent Keyser, professor of vision sciences, University of Alabama at Birmingham, noted that nicotine may be linked to the redness and visible blood vessels of rosacea.

"Smoking has been identified as the single most important cause of many vascular diseases," Dr. Keyser noted. "Although smoking would seem to discourage flushing as it acts to constrict the blood vessels, recent studies have shown that nicotine, acting in receptors on the cells that line blood vessels, can cause new blood vessels to form in the skin. This is a process known as neo-vascularization, and can induce the networking of capillaries."

In the study, researchers cultured blood vessel lining cells with and without nicotine and analyzed them with fluorescent imaging. The activation of nicotine receptors appeared to be associated with a significant increase in intracellular calcium, and also stimulated two major signaling proteins that may trigger a cascade of biochemical reactions associated with rosacea.

"The increase in intracellular calcium is especially significant as it is a very potent force in triggering cellular reactions that may lead to the formation of new blood vessels," Dr. Keyser said. The study is continuing in order to determine the potential short-term effects of nicotine on gene expression and the consequences of long-term exposure.

A recent study in the Journal of the American Academy of Dermatology also documented that the skin of individuals with rosacea is significantly more sensitive to heat.

Patients with rosacea "often complain of increased skin sensitivity and frequently describe a burning sensation," said Dr. Daniela Guzman-Sanchez and colleagues of the Wake Forest University School of Medicine.¹ The scientists noted that although this heightened sensitivity is well recognized in practice, there had been no formal research on the phenomenon.

In their study of 24 individuals, 16 had rosacea, half with subtype 1 (erythematotelangiectatic) rosacea, characterized by redness and flushing, and half with subtype 2 (papulopustular) rosacea, characterized by bumps and pimples. The remaining eight individuals served as a control group without rosacea.

All of the study subjects were exposed to a device that warmed the skin of the cheek beginning at almost 90 degrees Fahrenheit, with a potential high of about 122 degrees. Individuals were asked to rate their perception of burning, and skin blood flow and skin temperature were also measured.

The researchers found that individuals with both subtypes of rosacea had a significantly greater sensitivity to heat pain on symptomatic skin, compared to skin without symptoms and to the skin of individuals without rosacea. Moreover, when patients rated pain themselves, there was a significantly greater perception of pain in the subtype 1 group with flushing than in those with subtype 2 rosacea.

Skin blood flow was significantly higher in areas with bumps and pimples than in normal skin.

Associated Reference

1. Guzman-Sanchez D, Ishiuji Y, Patel T, Fountain J, Chan YH, Yosipovitch G. Enhanced skin blood flow and sensitivity to noxious heat stimuli in papulopustular rosacea. Journal of the American Academy of Dermatology. 2007;57:800-805.