Would a diagnosis of pilonidal cyst with abscess be appropriate without an open wound or drainage?

Diagnosis: Pilonidal Cyst with Localized Soft Tissue Infection (Not Abscess)

The appropriate diagnosis in this case is pilonidal cyst with localized soft tissue infection or cellulitis, not abscess, because the physical examination explicitly documents absence of fluctuance and no drainage—both essential features of an abscess. 1

Key Diagnostic Distinctions

Defining Features of an Abscess

• Fluctuance is the hallmark physical finding that distinguishes a mature abscess from other soft tissue infections 1
• Purulent drainage when present confirms abscess formation 1
• Your examination specifically states "no fluctuance or drainage," which excludes the diagnosis of abscess 1

What You Actually Have

• Hard, tender induration (2 cm) with localized erythema represents either:
  • Early inflammatory phase of pilonidal disease recurrence 2
  • Localized cellulitis/soft tissue infection around the pilonidal cyst site 3
  • Pre-abscess phlegmon that has not yet organized into a drainable collection 1

Clinical Reasoning Algorithm

When to Diagnose "Abscess"

• Fluctuance on palpation is present 1
• Purulent drainage is visible or expressible 1
• Imaging (if obtained) demonstrates a fluid collection 3

When to Diagnose "Soft Tissue Infection" or "Cellulitis"

• Induration, erythema, warmth, and tenderness without fluctuance 3, 1
• Systemic signs (fever, tachycardia) may be present but no drainable collection 1
• This is your patient's current presentation 1

Management Implications of Correct Diagnosis

Your Current Approach is Appropriate

• Antibiotics are indicated for soft tissue infection with systemic signs (intermittent fevers, localized heat) even without abscess 1, 4
• IM ceftriaxone and oral antibiotics cover the typical mixed flora of pilonidal infections 4
• Warm soaks may help the infection either resolve or mature into a drainable abscess 5

Critical Monitoring Points

• Watch for development of fluctuance over the next 48-72 hours, which would indicate abscess formation requiring incision and drainage 3, 1
• Spreading erythema >5 cm beyond the induration warrants more aggressive antibiotic therapy 1
• Worsening systemic signs (fever >38.5°C, tachycardia >110 bpm) indicate need for urgent surgical evaluation 3, 1

Common Pitfall to Avoid

Do not label every tender, inflamed area as an "abscess"—this leads to inappropriate attempts at incision and drainage when no drainable collection exists, potentially worsening tissue trauma and delaying appropriate antibiotic treatment 3, 1. The absence of fluctuance means there is no organized pus collection to drain 1.

If Abscess Develops Later

• Pilonidal abscesses require incision and drainage as definitive treatment 3
• Antibiotics alone are insufficient once an abscess has formed 3, 4
• The current hard induration may evolve into a fluctuant abscess requiring drainage in 2-5 days if antibiotic therapy is inadequate 1

Documentation Recommendation

Appropriate diagnostic terminology:

• "Pilonidal cyst with localized soft tissue infection/cellulitis" 3, 1
• "Recurrent pilonidal disease with surrounding cellulitis" 2
• "Pilonidal cyst with pre-abscess phlegmon" 1

Avoid: "Pilonidal abscess" when fluctuance and drainage are absent 1