What is the rate of appendicitis recurrence in a patient with a history of appendicitis?

Rate of Appendicitis Recurrence

The recurrence rate of appendicitis depends critically on the initial treatment approach and disease severity: approximately 27-39% within 1-5 years after antibiotic treatment for uncomplicated appendicitis, and 12-24% after non-operative management of complicated appendicitis (abscess/phlegmon).

Recurrence After Antibiotic Treatment for Uncomplicated Appendicitis

The evidence from the highest-quality randomized trial demonstrates a progressive increase in recurrence risk over time:

• Within 1 year: 27.3% of patients initially treated with antibiotics required appendectomy 1
• At 5 years: The cumulative recurrence rate reaches 39.1%, with most recurrences occurring in the first year 2
• Late recurrences (after year 1): An additional 16.1% of patients who avoided surgery in the first year eventually required appendectomy between years 1-5 2

The 2020 World Society of Emergency Surgery (WSES) guidelines confirm these findings, reporting a 1-year recurrence rate of 27.4% following antibiotic-first treatment 1. Importantly, approximately 8% of patients fail antibiotic treatment during the initial hospitalization, requiring immediate appendectomy 1.

Key Prognostic Factors

The presence of an appendicolith is the single most important predictor of treatment failure, significantly increasing both perforation risk and recurrence rates after non-operative management 1. Other factors associated with successful antibiotic treatment include:

• Duration of symptoms >24 hours before admission 1
• Lower temperature at presentation 1
• Modified Alvarado score <4 1
• Smaller appendiceal diameter on imaging 1
• Age <60 years, CRP <60 g/L, and WBC <12 × 10⁹/L 1

Recurrence After Non-Operative Management of Complicated Appendicitis

For patients with perforated appendicitis, appendiceal abscess, or phlegmon treated conservatively:

• Recurrence rate ranges from 12-24% across multiple studies 1
• In children specifically, the recurrence rate is approximately 12-20.5% 1
• The CHINA randomized trial in children found exactly 12% developed histologically proven recurrent appendicitis during active observation 1

Clinical Severity of Recurrent Episodes

Recurrent appendicitis typically presents with milder clinical features than the initial episode 3. Patients with recurrence demonstrate:

• Lower white blood cell counts (median 9.5 vs 13.1 at initial presentation) 3
• Lower maximum temperatures (98.6°F vs 100.3°F) 3
• Shorter duration of IV antibiotic therapy needed (3 vs 6 days) 3
• Shorter hospital stays (6 vs 7 days) 3

Long-Term Outcomes and Complications

The 5-year APPAC trial follow-up revealed critical safety data:

• Overall complication rate was significantly lower in the antibiotic group (6.5%) compared to immediate appendectomy (24.4%) 1, 2
• Of patients who underwent delayed appendectomy for recurrence, 82.9% had uncomplicated appendicitis, 10% had complicated disease, and 7.1% had no appendicitis 1
• No intra-abdominal abscesses or major complications occurred from delayed appendectomy 1

Special Considerations

Age-Related Factors

Patients ≥40 years with complicated appendicitis have a significantly elevated risk of underlying neoplasm (3-17%), which argues against routine observation in this age group 1. The Mällinen trial was prematurely terminated due to a 17% neoplasm rate in patients >40 years treated non-operatively for periappendicular abscess 1.

Gender Differences

Male gender is an independent risk factor for recurrence (HR 3.45; 95% CI 1.15-10.39) following successful non-operative treatment 4.

Clinical Implications

Approximately 60-73% of patients treated with antibiotics for uncomplicated appendicitis will avoid appendectomy long-term 1, 2. This means routine interval appendectomy would subject 6-8 patients to unnecessary surgery to prevent recurrence in only 1-2 patients 1. The WSES strongly recommends against routine interval appendectomy in patients <40 years, reserving surgery only for those who develop recurrent symptoms 1.

Common Pitfalls to Avoid

• Do not assume all patients require interval appendectomy after successful non-operative management—the majority will never experience recurrence 1
• Do not overlook appendicoliths on imaging, as their presence substantially increases failure and recurrence rates 1
• Do not fail to screen patients ≥40 years with colonoscopy and CT after non-operative treatment of complicated appendicitis due to high neoplasm risk 1
• Do not dismiss the patient's preference—those wishing to avoid surgery must understand the 27-39% recurrence risk within 5 years 1, 2