Primary versus secondary closure of cutaneous abscesses in the emergency department: a randomized controlled trial.

OBJECTIVES: Cutaneous abscesses have traditionally been treated with incision and drainage (I&D) and left to heal by secondary closure. The objective was to compare the healing rates of cutaneous abscesses following I&D after primary or secondary closure.

METHODS: This was a randomized, controlled, trial, balanced by center, with blocked randomization created by a random-number generator. One urban and one suburban academic emergency department (ED) participated. Subjects were randomized to primary or secondary wound closure following I&D of the abscess. Main outcome measures were the percentage of healed wounds (wound was completely closed by visual inspection; a 40% difference in wound healing was sought) and overall failure rate (need for additional intervention including suture removal, additional drainage, antibiotics, or admission within 7 days after drainage).

RESULTS: Fifty-six adult patients with simple localized cutaneous abscesses were included; 29 were randomized to primary closure, and 27 were randomized to secondary closure. Healing rates at 7 days were similar between the primary and secondary closure groups (69.6%, 95% confidence interval [CI] = 49.1% to 84.4% vs. 59.3%, 95% CI = 40.7% to 75.5%; difference 10.3%, 95% CI = -15.8% to 34.1%). Overall failure rates at 7 days were also similar between the primary and secondary closure groups (30.4%, 95% CI = 15.6% to 50.9% vs. 28.6%, 95% CI = 15.2% to 47.1%; difference 1.8%, 95% CI = -24.2% to 28.8%).

CONCLUSIONS: The rates of wound healing and treatment failure following I&D of simple abscesses in the ED are similar after primary or secondary closure. The authors did not detect a difference of at least 40% in healing rates between primary and secondary closure.