Figure 2.

Difference in Cure Rates* by Abscess Cavity Diameter^† Among Participants with a Drained Skin Abscess Treated with Trimethoprim-Sulfamethoxazole Compared to Placebo.

Overall, for trimethoprim-sulfamethoxazole and placebo groups, clinical cure rate at 7–14 days was 92.9% and 85.7% (difference, 7.2; 95% CI 3.2–11.2), composite cure rate at 7–14 was 86.5% and 74.3% (12.2; 95% CI 7.2–17.1) and extended composite cure at 42–56 days was 82.4% and 70.2% (difference, 12.2; 95% CI 6.8–17.6), respectively.

* The between–group percentage point differences in cure rates were plotted by 1 cm increments of abscess cavity or erythema dimension. For each increment, cure rates were calculated for those that had the same or smaller size lesion. Outcomes were defined as follows: clinical cure was defined as resolution of all symptoms and signs of infection, or improvement such that no new antibiotics were prescribed (through 7–14 days after the end of treatment); composite cure was defined as resolution of all symptoms and signs of infection, or improvement such that no additional antibiotics and/or surgical drainage procedure were required (through 7–14 days and 42–56 days after the end of treatment).

^†Diameter was defined as the maximal linear dimension (length or width) of the abscess cavity, by probe after incision, and erythema, measured on the skin.