What is the initial step in managing a case of abscess?

Initial Management of Abscess

The initial step in managing an abscess depends critically on its location and the patient's clinical status, but for most abscesses, incision and drainage is the primary intervention, with imaging (CT) reserved for deep or complex collections that cannot be adequately assessed clinically.

Clinical Assessment and Decision Algorithm

For Superficial Skin and Soft Tissue Abscesses

• Incision and drainage is the definitive treatment for simple cutaneous abscesses in immunocompetent patients 1.
• Most large furuncles and all carbuncles should be treated with incision and drainage 1.
• CBC and routine cultures are NOT indicated for simple abscesses in patients with normal host defenses 1, 2.
• Antibiotics are unnecessary unless fever or systemic signs of infection (SIRS criteria) are present 1.

For Deep or Intra-abdominal Abscesses

A step-up diagnostic approach should be used, starting with clinical and laboratory examination, then proceeding to imaging based on clinical suspicion and available resources 1.

When to Obtain CT Imaging:

• CT with IV contrast is indicated when deep abscess is suspected (intra-abdominal, hepatic, diverticular) to confirm diagnosis, determine size, and guide treatment strategy 1.
• Imaging findings guide whether percutaneous drainage, antibiotics alone, or surgical intervention is needed 1.
• For perianal/perirectal abscesses, diagnosis is usually clinical and imaging is not routinely required 1.

Treatment Based on Abscess Characteristics:

Small abscesses (<3-5 cm):

• May be treated with antibiotics alone in immunocompetent, clinically stable patients 1.
• Antibiotic therapy for 7 days is appropriate for small diverticular abscesses 1.

Large abscesses (>5 cm):

• Percutaneous drainage combined with antibiotics is the preferred initial approach 1, 3.
• Percutaneous drainage should be performed for large diverticular abscesses with antibiotic therapy for 4 days if source control is adequate 1.

When percutaneous drainage is not feasible:

• In immunocompetent, non-critically ill patients: antibiotics alone may be considered with careful clinical monitoring 1.
• In critically ill or immunocompromised patients: surgical intervention should be considered as primary treatment 1.

Laboratory Testing Role

CBC should be obtained selectively, not routinely:

• Indicated in patients with systemic signs of infection to assess for SIRS criteria (WBC >12,000 or <4,000 cells/µL) 1.
• Elevated WBC count and inflammatory markers (CRP, procalcitonin) help guide antibiotic duration and need for intervention 1.
• Laboratory markers alone do not mandate specific treatment but inform clinical decision-making 1.

Common Pitfalls to Avoid

• Do not delay drainage of accessible abscesses while waiting for imaging or laboratory results in clinically stable patients 1.
• Avoid routine cultures and antibiotics for simple skin abscesses in immunocompetent patients—this adds unnecessary cost without improving outcomes 4, 2.
• Do not perform surgical exploration as initial management unless the patient is hemodynamically unstable with peritonitis or the abscess is not amenable to percutaneous drainage 1.
• For perianal abscesses, do not actively search for fistula tracts at initial drainage—simply drain adequately 1.

Summary Algorithm

1. Clinical assessment first: Determine abscess location, size (if palpable), and patient stability
2. Superficial abscess: Proceed directly to incision and drainage
3. Suspected deep abscess: Obtain CT imaging to characterize and plan intervention
4. Based on imaging: Choose percutaneous drainage (preferred for large collections), antibiotics alone (small collections in stable patients), or surgery (critically ill, failed drainage, or inaccessible collections)
5. CBC: Obtain only if systemic signs present or to guide antibiotic therapy duration