A Randomized, Double-Blind, Placebo-Controlled Trial of Trimethoprim-sulfamethoxazole vs. Placebo for Patients with an Incised and Drained Cutaneous Abscess
U.S. emergency department (ED) visits for cutaneous abscess have increased corresponding with the emergence of methicillin-resistant Staphylococcus aureus (MRSA). The role of antibiotics for patients with a drained abscess is unclear.
We conducted a randomized double-blind, trial at 5 U.S. EDs to determine whether 7 days of trimethoprim-sulfamethoxazole (TMP/SMX 160 mg/800 mg BID) is superior to placebo for treatment of patients >12 years old with an acute uncomplicated skin abscess receiving drainage and treated as an outpatient. The primary outcome was clinical cure of the abscess at the test-of-cure visit (TOC, 7-14 days after the end of treatment) in the per-protocol (PP) population.
Of 1,265 patients enrolled, 1,247 (98.6%) were randomized to TMP/SMX or placebo and received ≥1 dose. Subjects were median age 35 years (range, 14-73). Median maximal dimension of the abscess cavity and associated erythema were 2.5 cm and 6.5 cm, respectively; 44.3% grew MRSA. In the PP population, clinical cure occurred in 487/ 524 (92.9%) TMP/SMX-treated compared to 457/533 (85.7%) placebo-treated subjects (difference 7.2%; 95% CI 3.2%-11.2%). Similar differences were found for abscess cure in the intention-to-treat populations. Compared to the placebo group, the TMP/SMX group had lower rates of subsequent hospitalization (19/524 [3.6%] vs. 34/533 [6.4%]; difference -2.8%; 95% CI -5.6%-0.1%), surgeries (18/524 [3.4%] vs. 46/533 [8.6%]; difference -5.2%; 95% CI -8.2%--2.2%), new skin infections at a different location (16/524 [3.1%] vs. 55/533 [10.3%]; difference -7.3%; 95% CI -10.4%- ‑4.1%), and similar infections in their household (9/524 [1.7%] vs. 22/533 [4.1%]; difference ‑2.4%; 95% CI -4.6%--0.2%) through TOC. At 42-56 days after treatment, new infection rates were 10.9% (57/524) in TMP/SMX- and 19.1% (102/533) in placebo-treated subjects (difference -8.3%; 95% CI -12.7%- -3.8%). TMP/SMX was associated with slightly more, mostly mild, gastrointestinal side effects. There were no serious drug-related adverse events.
Compared to placebo, TMP/SMX is safe and associated with improved outcomes for patients with an acute cutaneous abscess receiving drainage and treated as an outpatient.
NIAID/NIH/DHHS: Research Contractor, Research support
F. Abrahamian, None
A. Krishnadasan, None
F. Lovecchio, None
D. Karras, None
M. Steele, None
R. Rothman, None
G. Moran, None