I have a rapidly enlarging perianal abscess and have just taken my first dose of amoxicillin/clavulanate (Augmentin); should I wait for the antibiotic or go to the emergency department for incision and drainage?

Go to the Emergency Department Immediately for Incision and Drainage

Do not wait for antibiotics to work—proceed directly to the emergency department for urgent surgical drainage of your perianal abscess. Antibiotics alone are inadequate treatment and will not resolve the abscess; incision and drainage is mandatory for all perianal abscesses regardless of antibiotic therapy 1.

Why Antibiotics Alone Will Fail

• Surgical drainage is the cornerstone of treatment for all perianal abscesses, and antibiotics cannot substitute for definitive source control 1.
• An undrained perianal abscess will continue to expand into adjacent tissue spaces and can progress to life-threatening systemic infection 1.
• Antibiotics are not routinely indicated after adequate surgical drainage in most patients, meaning the Augmentin you've taken addresses a secondary concern, not the primary problem 1.

Timing Is Critical—You Need Urgent Drainage

Your situation warrants emergency or urgent drainage based on the following framework 1:

Emergency Drainage (Go Immediately) If You Have:

• Rapidly enlarging abscess (which you describe) 1
• Fever, chills, or any signs of systemic infection/sepsis 1
• Diabetes mellitus 1
• Any immunosuppression (steroids, chemotherapy, HIV, etc.) 1
• Diffuse cellulitis or redness spreading beyond the abscess itself 1

Urgent Drainage Within 24 Hours:

• Even without the above high-risk features, surgical drainage should ideally be performed within 24 hours of diagnosis 1.

Why Waiting Is Dangerous

• Inadequate or delayed drainage is the principal cause of abscess recurrence, with recurrence rates up to 44% when drainage is insufficient 1.
• Incomplete source control (an undrained or partially drained abscess) is one of the few indications where antibiotics are recommended—but only as an adjunct to drainage, never as monotherapy 1.
• The longer you wait, the higher your risk of the abscess extending into deeper spaces (horseshoe abscess, supralevator extension) or causing systemic sepsis 1.

What About the Augmentin You Just Started?

• Antibiotics have no influence on anal fistula formation or recurrent abscess after proper incision and drainage, based on a 2024 randomized trial comparing amoxicillin/clavulanate (the exact drug you're taking) versus no antibiotics 2.
• The antibiotic may help control surrounding cellulitis or prevent systemic spread temporarily, but it will not drain the pus collection 1.
• If you proceed to drainage (which you must), antibiotics are only continued post-operatively if you have sepsis, extensive cellulitis, immunosuppression, or incomplete drainage 1.

What to Expect at the ED

• The emergency physician or surgeon will perform incision and drainage, ideally keeping the incision close to the anal verge to minimize potential fistula length 1.
• Complete drainage is essential—timid or inadequate incisions are a leading cause of treatment failure 1.
• If a fistula is found during drainage and it is low-lying without sphincter involvement, a fistulotomy may be performed; if the sphincter is involved, a loose seton will be placed 1.
• Post-operative packing is controversial and may not be necessary 1.

Common Pitfalls to Avoid

• Do not rely on antibiotics alone—this is the most critical error and will lead to treatment failure 1.
• Do not delay seeking drainage because you just started antibiotics today—the clock is ticking on potential complications 1.
• Do not assume the abscess will resolve on its own—perianal abscesses require surgical intervention 1.