Can antibiotics prevent cellulitis from coming back?

Photo of an elderly man taking antibiotics
PantherMedia / Kasia Bialasiewicz

People who have already had cellulitis can prevent it from returning by taking low-dose penicillin. When used for this purpose, the penicillin is taken every day for up to twelve months. This preventive treatment is safe and well tolerated.

Cellulitis is a bacterial skin that can arise if bacteria get into injured skin, cracked skin or a sore and infect the deeper layers of skin. It can usually be treated successfully with .

Some people get cellulitis again and again. This is thought to happen in about one third of all people who have had cellulitis. Doctors will try to find the cause of the new and treat it. Possible causes include skin conditions like athlete's foot or impetigo, as well as poorly controlled diabetes.

If treating the cause doesn't help stop cellulitis from returning, preventive treatment with can help. This involves taking twice a day over a long time period. Alternatively, the can be injected into a muscle every 14 days.

Research on preventive treatment with penicillin

Various groups of researchers have looked into the possible advantages and disadvantages of preventive treatment with in people who keep getting erysipelas or cellulitis infections. The researchers found five studies with a total of about 500 patients.

Two of the five studies were particularly conclusive because quite a lot of people took part in them and they were designed and carried out well. Both of the studies also kept in touch with the participants for three years to see whether the skin returned. This meant that they were able to provide information about how well the worked in the long term.

In one study, the participants had cellulitis for the first time. They were randomly assigned to two groups. One group was given penicillin for six months, and the other was given a placebo (fake drug) for six months. The dose of penicillin taken was 500 mg per day (two 250 mg tablets), which is quite a small dose. In the other study, participants had to have had cellulitis at least twice already. The treatment was the same as in the first study, but lasted twelve months instead.

Antibiotics lower the risk of further infections

When analyzed together, the results of these two studies showed that taking penicillin over a long period of time prevents further infections. During the three years in which the researchers stayed in touch with the study participants,

  • 43 out of 100 people who were given the placebo developed a new bacterial skin .
  • 32 out of 100 people who were given penicillin developed a new bacterial skin .

In other words, penicillin prevented 11 out of 100 people from getting another during this time period.

Low-dose penicillin is well tolerated

Both studies also looked into how common side effects were. The researchers were especially interested in nausea, diarrhea, rashes and fungal infections because these side effects are often associated with .

The results showed that these side effects weren't more common in the penicillin group than they were in the placebo group. So, if people take penicillin and have diarrhea, for instance, it doesn't necessarily mean that the diarrhea was a side effect of the medication.

The reason why the were so well tolerated in the studies might be because they were taken in such small doses. But even low-dose might still cause side effects sometimes. Although a few hundred people took part in the studies, the total number of participants isn't enough to draw conclusions about rare side effects.

Some people aren't able to take penicillin at all because they are allergic to it – but this is very uncommon. If you take , it's always a good idea to find out how to use them properly. The incorrect use of can make become resistant to these drugs, and then they no longer work properly.

Dalal A, Eskin-Schwartz M, Mimouni D, Ray S, Days W, Hodak E et al. Interventions for the prevention of recurrent erysipelas and cellulitis. Cochrane Database Syst Rev 2017; (6): CD009758.

Oh CC, Ko HC, Lee HY, Safdar N, Maki DG, Chlebicki MP. Antibiotic prophylaxis for preventing recurrent cellulitis: a systematic review and meta-analysis. J Infect 2014; 69(1): 26-34.

Thomas K, Crook A, Foster K, Mason J, Chalmers J, Bourke J et al. Prophylactic antibiotics for the prevention of cellulitis (erysipelas) of the leg: results of the UK Dermatology Clinical Trials Network's PATCH II trial. Br J Dermatol 2012; 166(1): 169-178.

Thomas KS, Crook AM, Nunn AJ, Foster KA, Mason JM, Chalmers JR et al. Penicillin to prevent recurrent leg cellulitis. N Engl J Med 2013; 368(18): 1695-1703.

IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. informedhealth.org can provide support for talks with doctors and other medical professionals, but cannot replace them. We do not offer individual consultations.

Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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Updated on February 22, 2018
Next planned update: 2021

Authors/Publishers:

Institute for Quality and Efficiency in Health Care (IQWiG, Germany)

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