For patients who have a single, small skin abscess, the addition of oral antibiotics to standard incision and drainage of the lesion improves cure rates and decreases recurrence rates, according to a study published online June 28 in the New England Journal of Medicine.
The results of this multicenter prospective randomized double-blind placebo-controlled trial, taken together with those of another recent large study, “call into question the perception – largely based on expert opinion or smaller, underpowered, and lower-quality noninferiority trials – that cure rates do not improve with the addition of systemic antibiotic treatment after incision and drainage,” said Robert S. Daum, MD, professor of pediatrics at the University of Chicago, and his associates.
The trial involved 786 patients of all ages (64% were adults and 36% were children; mean age was 25.5 years) who had a single, uncomplicated skin abscess of 5 cm or smaller and were treated at the University of Chicago; San Francisco General Hospital; Harbor-UCLA Medical Center; Vanderbilt University Medical Center, Nashville; Washington University, St. Louis; or Emory University, Atlanta. A total of 266 patients were assigned to receive oral clindamycin, 263 to receive oral trimethoprim–sulfamethoxazole (TMP-SMX), and 257 to receive matching placebo for 10 days after the lesions were incised and drained.
At follow-up 7-10 days following the conclusion of treatment, the rates of clinical cure were 83.1% with clindamycin and 81.7% with TMP-SMX, both significantly greater than the 68.9% cure rate with placebo (P less than .001 for both comparisons). Similarly, at 1-month follow-up, 78.6% of the clindamycin group and 73.0% of the TMP-SMX group “remained cured,” compared with 62.6% of the placebo group (N Engl J Med. 2017 June 28. doi: 10.1056/NEJMoa1607033).
Among those with cultures positive for Staphylococcus aureus, cure rates 7-10 days after treatment ended were 83.5% and 83.2% in the clindamycin and TMP-SMX groups, respectively, significantly higher than in the placebo group (63.8%). Among those positive for methicillin-resistant S. aureus, cure rates were 81.7% and 84.6% in the clindamycin and TMP-SMX groups, respectively, significantly higher than in the placebo group (62.9%).
The rate of treatment-associated adverse events was higher with clindamycin (21.9%) than with TMP-SMX (11.1%) or with placebo (12.5%). The most common adverse events were diarrhea and nausea, which were mild to moderate in severity and resolved with sequelae. There were no cases of Clostridium difficile–associated diarrhea or severe allergic reactions. One patient had a hypersensitivity reaction that was considered to be related to TMP-SMX, which involved fever, rash, thrombocytopenia, and hepatitis and which resolved without sequelae.
The National Institute of Allergy and Infectious Diseases and the National Center for Research Resources supported the study. Dr. Daum reported ties to Pfizer, Dynavax, Theravance, and Merck, and his associates reported ties to numerous industry sources.