Two recent studies, funded by individual donations to the National Rosacea Society (NRS), have discovered potential key factors in the development of rosacea that open new possibilities for important advances in its treatment and prevention.

A malfunction in part of the body’s nervous system may be linked to the redness as well as the bumps and pimples of rosacea, according to a recently completed study by Dr. Akihiko Ikoma and colleagues at the University of California-San Francisco.

The investigators took blood and biopsy samples from members of 10 families in which some individuals had rosacea. Through innovative biochemical and genetic testing, they found those with rosacea suffered from irregularities in a variety of transient receptor potential (TRP) ion channels, which serve as prominent components of the nervous system. Because a variety of TRP channels can be activated by factors that trigger rosacea symptoms, the researchers noted, impaired functioning of these channels may play a critical role in the development of the disorder.

For example, TRPV1 is activated by capsaicin, a substance present in spicy food, as well as by heat or under inflammatory conditions. TRPV2 may play a role in innate immunity, inflammation and the sensing of heat. TRPV4 is also activated by moderate heat and may promote flushing, stinging and burning.

The researchers also found the immune system of those with subtype 1 (erythematotelangiectatic) rosacea, characterized by flushing and redness, showed significantly increased reactivity for TRPV2 and 3, as well as gene expression of TRPV1. Subtype 2 (papulopustular) rosacea, characterized by bumps and pimples, showed enhanced reactivity of the immune system for TRPV2 and 4, and had gene expression of TRPV2. These TRP nerve channels may therefore be promising targets in the development of future rosacea therapy, the researchers said.

In a separate study of 27 patients with subtype 1 rosacea, 18 with subtype 2 rosacea, 19 with photodamaged skin and prominent telangiectasia and 11 control subjects without rosacea or sun damage, Dr. Yolanda Helfrich, assistant professor at the University of Michigan, found that patients with subtype 1 rosacea had a greater number of mast cells that were discharging their contents than the control subjects.

Mast cells are found in skin tissue surrounding blood vessels and nerves, and release many mediators involved in rosacea, including histamine, associated with flushing. Since virtually all the mast cells in the rosacea patients were positive for interleukin 17, Dr. Helfrich noted that this cytokine – which plays a key role in development of rheumatoid arthritis and psoriasis – may also contribute to rosacea.

In addition, though some individuals with skin aging due to sun exposure also had prominent facial telangiectasia, she found significant biological differences between this group and those with rosacea, suggesting that the presence of visible blood vessels alone should not necessarily lead to a diagnosis of rosacea.