Case vignette: A 24yo M with no past medical history presents with a "boil" on his lower back that he noticed a couple days ago. The boil has been slowly increasing in size and becoming more tender. He denies fever, chills, nausea, vomiting, or history of previous abscesses. On exam there is a 3cm cutaneous abscess with confirmed fluid pocket on ultrasound, and there is minimal surrounding erythema or induration. You decide to incise and drain (I&D) the abscess, including probing to break up loculations and manual decompression, but you are not sure whether you need to irrigate the cavity.
Article: Chinnock B, Hendey GW. Irrigation of Cutaneous Abscesses Does Not Improve Treatment Success. Annals of Emergency Medicine. 2016 March; 67(3): 379-383.
Study objective: To determine whether irrigation of cutaneous abscess cavity after I&D in the emergency department (ED) decreases the need for further intervention within 30 days.
Methods: A single-center, prospective, randomized, nonblinded controlled trial of 187 patients randomized to irrigation or no irrigation after I&D of a cutaneous abscess. Thirty-day telephone follow-up was conducted examining for further intervention need (repeated I&D, antibiotic change, or abscess-related admission).
Inclusion/exclusion criteria: Included a convenience sample of patients >18yo with a cutaneous abscess, excluded patients who were pregnant, in police custody or prisoners, admitted to the hospital, got an operating room I&D, or were unable to follow up in 48 hours.
Results: 187 (92%) patients completed follow up and were included in final analyses. There was no difference in failure to follow up between the groups. The primary outcome evaluated (need for additional treatment) was statistically the same between groups (15% in irrigation group vs 13%; difference 2%; 95%CI –8% to 12%). There was also no difference in pain scale scores. Differences between the two groups included the irrigation group more likely to receive both packing (89% vs 75%; difference 14%; 95%CI 4-25%) and outpatient antibiotics (91% vs 73%; difference 18%; 95%CI 7-29%).
Discussion: Per our literature review, this is the only randomized, well constructed trial testing the benefit of irrigation of cutaneous abscess in the ED. One article weakness is the difference in packing and antibiotics use between the study groups, although both are controversial and ACEP does not recommend the routine use of antibiotics after routine I&D. Additionally, the nonconsecutive enrollment, single-center location, and extensive exclusion criteria limit the generalizability.
Case conclusion: You remember a recent study in Annals and decide to not irrigate but instead apply a dry gauze dressing to the wound. Before discharging the patient, another internal argument arises… to prescribe antibiotics or not.
Take home: The results of the study demonstrate that irrigation after I&D of a simple cutaneous abscess provides no clinical benefit at 30 days. However, this should be taken with a grain of salt as there were some methodological flaws and limited patient population.
Written by:
Dr. Matt Hughes, MD
Emergency Medicine, PGY-2
Cook County Health
Reviewed by:
Dr. Robert Needleman, MD
Assistant Program Director
Cook County Health