SDEF: Treatments for Rosacea Contribute to Growth of Antibiotic Resistance

WAILEA, Hawaii, Feb. 17 -- Using antibiotics to treat rosacea -- a regimen that has no basis in evidence but a long history in daily clinical practice -- has contributed to antibiotic resistance, according to a review of the latest evidence.

The primary suspects in this case are the tetracyclines, particularly doxycycline, explained Hilary E. Baldwin, M.D., an associate professor and vice-chair of the department of dermatology at SUNYDownstate Medical Center in New York.

And, in a surprising finding, resistance to doxycycline can occur in a few days, with resistant bacteria in abundance after just seven days of treatment with 100 mg doxycyline daily, she said.

Dr. Baldwin reviewed rosacea treatments during a presentation at the Skin Disease Education Foundation Hawaii Dermatology Seminar.

She said that antibiotics became a standard rosacea treatment because of the mistaken belief that "the etiology of rosacea was bacterial. But the best current evidence is that microbes are not involved."

Yet, antibiotics continue to be a standard course because they "appear to be effective for treatment of papulopustular rosacea," she said.

But tetracyclines work, Dr. Baldwin explained, not because of their antibiotic properties but because "they have anti-inflammatory activity."

Specifically, tetracyclines are involved in downregulation of proinflammatory cytokines, inhibition of angiogenesis, inhibition of neutrophil chemotaxis, inhibition of nitric oxide activity, and suppression of neutrophil-derived production of reactive oxygen species -- all of which help them take the red out of rosacea.

But doxycycycline at 40 mg controlled dose or 20 mg bid is an anti-inflammatory dose that has no antibiotic effect so it will not promote resistance. She cautioned, however, that simply cutting a 75 mg generic doxycycline pill in half does not achieve a guaranteed anti-inflammatory effect, she said. "The low does must be administered in a dose specific pill at 40 mg or 20 mg," she said.

But she warned that "giving 100 mg every other day, is not an anti-inflammatory dose."

The 100 mg every other day actually promotes antibiotic resistance because it is starting and stopping an antibiotic regimen.