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New study could reduce antibiotic use for common skin infection

Southampton researchers are testing a shorter course of antibiotics to treat cellulitis.

Cellulitis is a deep skin infection that’s treated with antibiotics.

However, antibiotics can cause side effects - and levels of resistance are rising. This means doctors are looking at ways to cut any unnecessary use.

The COAT study is funded by the National Institute for Health and Care Research (NIHR). It will help determine if a five-day course of antibiotics for cellulitis is as effective as the standard seven days.

Professor Nick Francis from the University of Southampton and the NIHR Southampton Biomedical Research Centre (BRC) is leading the study. It is being run by the Southampton Clinical Trials Unit (CTU).

Reducing antibiotic use

Cellulitis is a bacterial infection that affects the deep layers of the skin.

The infection is most common in older people and those with poor circulation or a weakened immune system.

Any area of the body can be affected but the legs are the most common place. The infection can spread if it’s not treated quickly.

Current guidelines suggest that people with cellulitis should be given a five to seven-day course of oral antibiotics.

“At the moment, almost all patients who come to their GP with cellulitis will be initially treated for the full seven days,” said Prof Francis. “This is not because of evidence from research, but more due to years of warnings to doctors about stopping treatment too soon.

“However, there is increasing evidence that shorter courses are as effective. Longer courses may increase risks for individual patients, as well as the entire healthcare system as we see increases in antibiotic resistance.”

Previous research has shown that shorter courses of antibiotics can be just as effective for other infections. These include pneumonia, tonsillitis and urinary infections.

But there is currently very little evidence for this approach for people with cellulitis. Prof Francis continued:

“This lack of evidence means GPs are reluctant to prescribe shorter courses for these patients. Our study will test whether five days of antibiotic treatment works as well as seven days to see if the guidelines can be changed.”

Gathering the evidence

Researchers are recruiting 350 patients with cellulitis in their legs. They will do this through GP surgeries across the UK.

Half will be given the standard seven-day course of the oral antibiotic flucloxacillin. The other half will take antibiotics for five days, followed by a placebo pill for two days.

“The patients will be randomly assigned to each arm of the trial and will not know whether they are having the full course of antibiotics or the shorter course and placebo,” said Sophie Varkonyi-Clifford, Trial Manager at the Southampton CTU.

“Patients will report pain and other symptoms related to cellulitis before they start treatment and for a month afterwards. Their local GP surgery will also note any additional treatment or complications for the next year.”

Prof Francis added: “We hope the outcomes of this trial will definitively show whether cellulitis can be effectively treated with a five-day course of antibiotics.

“If the results are positive, it could lead to an update in the guidelines and a reduction in the amount of these drugs being routinely prescribed by GPs across the UK. This would be beneficial for patients and the entire health service.”

Visit the COAT study website for more information.


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