Rosacea the result of a trifecta of unfortunate factors

Aug 6 2007

Rosacea is a common inflammatory skin disease that causes facial redness which affects as many as 14 million Americans.

Although sufferers learn through experience triggers which exacerbate the condition such as spicy foods, heat, alcohol, and even embarrassment, until now, it was unclear what actually causes Rosacea.

Researchers the University of California, San Diego (UCSD) say two abnormal factors are the cause of Rosacea.

The team led by professor of medicine Dr. Richard L. Gallo, found that the over-production of two interactive inflammatory proteins results in excessive levels of a third protein, which in turn causes the Rosacea effect.

Dr. Gallo, who is the chief of the division of Dermatology at the university says the effect is akin to lots of gasoline plus a match, which is the result of a trifecta of unfortunate factors in people with Rosacea.

In the past Rosacea has been called adult acne, and it usually affects people with fair skin, between the ages of 30 and 60.

However unlike acne, Rosacea is not associated with a skin infection by one type of bacteria, even though antibiotics are sometimes prescribed to treat its symptoms.

Rosacea is considered a chronic condition which worsens over time and is generally cyclic, flaring up for a period of weeks to months, and then subsiding for a time.

Current treatments are often not effective.

In their laboratory work Gallo and his team that saw that anti-microbial peptides, the small proteins of the body's host defense system, caused the exact same symptoms in the skin that Rosacea does, redness, an increase in visible blood vessels, and bumps or pimples.

The peptides also appeared to reacted to the same triggers.

Gallo says when they looked at patients with the disease, they saw that every one of them had far more peptides than normal.

In order to discover why these patients had abnormal peptides, the researchers examined the source of the molecules and they found that in Rosacea patients there was too much cathelicidin present in their skin.

Cathelicidin is the precursor form of such peptides and is known for its function to protect the skin against infection.

In other skin diseases, a deficiency of cathelicidin correlates with increased infection; in Rosacea patients a different form than found in people without the skin disorder was discovered.

It seems that patients with Rosacea also have greatly elevated levels of enzymes called stratum corneum tryptic enzymes (SCTE) and these enzymes are the culprits in turning the precursor into the disease-causing peptide.

The researchers found that by injecting mice with the cathelicidin peptides found in Rosacea, or adding SCTE, they increased inflammation in the mouse skin, thus proving that these abnormalities can cause the disease.

The researchers say too much SCTE and too much cathelicidin leads to the abnormal peptides that cause the symptoms of this disease, and antibiotics tend to alleviate the symptoms of Rosacea in patients because some of them work to inhibit these enzymes.

They believe their findings may influence the modification of Rosacea therapies and they suggest the practice of treating Rosacea as bacteria is not appropriate.

Experts say the revelation suggest targets for an eventual drug therapy.

The research was funded by the National Institutes of Health, the Rosacea Society and the Association for Preve