Intramuscular Benzathine Penicillin Reduced Incidence of Recurrent Cellulitis

Although intramuscular antibiotics had been suggested as a prevention strategy for recurrent cellulitis, the evidence is scarce.

This article is part of Infectious Disease Advisor’s in-depth coverage of IDWeek 2017™, which took place in San Diego, CA. Our staff will be reporting on the latest treatment advancements and research initiatives for skin infections. Check back regularly for highlights from IDWeek 2017.

In patients with recurrent cellulitis, intramuscular injection of 2.4 million units of benzathine penicillin every 4 weeks reduced the incidence of recurrence, according to recent research presented at IDWeek 2017, held October 4-8 in San Diego, California.

In this cohort study, 211 patients (58.3% men) received >3 prophylactic intramuscular injections (mean 7.9 doses) of 2.4 million units benzathine penicillin every 4 weeks within a 6-month period. Participants were followed up for 1 year after the first dose, and  incidence of cellulitis was compared in patients during both the prophylactic and nonprophylactic periods.

The incidence rate of recurrent cellulitis was significantly lower in the prophylactic period compared with the nonprophylactic period (0.31 vs 0.77 episodes/patient-year; P =.004). In a multivariate analysis, prophylactic penicillin injections were associated with a lower risk of recurrence (relative risk [RR] 0.30; 95% CI, 0.13-0.69; P =.005).

Causes of recurrent cellulitis included diabetes (35.4%), tinea pedis (33.5%), impaired venous drainage (9.7%), joint replacement of lower extremity (6.3%), and edema status (congestive heart failure 9.2%, chronic renal failure 7.3%, cirrhosis 3.9%).

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Both impaired venous drainage (RR 2.78, 95% CI 1.20-6.48; P =.018) and tinea pedis (RR 3.04, 95% CI 1.17-7.90; P =.02) were associated with an increased risk of recurrence.

According to the researchers, the present study “was the largest cohort that demonstrated intramuscular injection of 2.4 million units benzathine penicillin with 4-week interval significantly reduced the incidence of recurrent cellulitis.”

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Lin SH, Lee YL, Chen YY, Yeh YC, Liu CE. The efficacy of intramuscular benzathine penicillin for preventing recurrent cellulitis: a nationwide population-based study. Presented at: IDWeek 2017; October 4-8, 2017; San Diego, California. Poster 266.