What is the best antibiotic for a pilonidal cyst?

Best Antibiotic Treatment for Pilonidal Cyst

For a pilonidal cyst, incision and drainage is the primary treatment, with antibiotics only recommended when there are signs of surrounding cellulitis or systemic infection, in which case an antibiotic active against both Staphylococcus aureus and anaerobes should be used.

Understanding Pilonidal Cysts

Pilonidal cysts are infections of the skin and subcutaneous tissue, typically occurring in the sacrococcygeal region, associated with the presence of hair. They are considered acquired rather than congenital conditions 1.

Primary Treatment Approach

Surgical Management

• Incision and drainage is the recommended treatment for inflamed pilonidal cysts 2
• Surgical removal is the definitive treatment, with various techniques available including:
  • Excision with open or closed wound healing
  • Incision and curettage
  • Minimally invasive endoscopic approaches 3

When Antibiotics Are Indicated

Antibiotics are NOT the primary treatment for pilonidal cysts but should be used in specific circumstances:

1. Presence of surrounding cellulitis
2. Systemic inflammatory response syndrome (SIRS) with:
   • Temperature >38°C or <36°C
   • Tachypnea >24 breaths per minute
   • Tachycardia >90 beats per minute
   • White blood cell count >12,000 or <400 cells/µL 2
3. Markedly impaired host defenses

Recommended Antibiotic Regimens

When antibiotics are indicated, the following regimens are recommended based on the location of the pilonidal cyst (typically in the sacrococcygeal/perianal region):

For Mild to Moderate Infection:

Outpatient treatment:

• Metronidazole 500 mg every 8 hours PLUS one of the following:
  • Ciprofloxacin 400 mg IV every 12 h or 750 mg PO every 12 h
  • Levofloxacin 750 mg every 24 h
  • Ceftriaxone 1 g every 24 h 2

For Severe Infection:

Inpatient treatment:

• Vancomycin 15 mg/kg every 12 h PLUS one of the following:
  • Piperacillin-tazobactam 3.375 g every 6 h or 4.5 g every 8 h IV
  • A carbapenem (imipenem-cilastatin, meropenem, or ertapenem)
  • Ceftriaxone 1 g every 24 h + metronidazole 500 mg every 8 h IV 2

Special Considerations

Microbiology

• Pilonidal cysts often contain mixed aerobic-anaerobic bacteria
• Common organisms include:
  • Staphylococcus aureus (including potential MRSA)
  • Anaerobic bacteria (including Bacteroides species) 4

Duration of Therapy

• For mild to moderate infections: 5-7 days of antibiotics
• For severe infections: 7-14 days, depending on clinical response 2

Recurrent Pilonidal Cysts

• A recurrent abscess at a site of previous infection should prompt a search for local causes such as a pilonidal cyst 2
• Recurrent cysts should be drained and cultured early in the course of infection
• Consider a 5-10 day course of an antibiotic active against the pathogen isolated 2

Pitfalls to Avoid

1. Treating with antibiotics alone - surgical drainage is essential
2. Using narrow-spectrum antibiotics - coverage must include both aerobic and anaerobic organisms
3. Delaying surgical consultation for severe infections
4. Failing to consider MRSA in patients with risk factors or in areas with high MRSA prevalence
5. Not addressing hair removal in the affected area, which can contribute to recurrence 5

Remember that while antibiotics may be necessary in certain cases, the definitive treatment for pilonidal cysts remains surgical intervention with appropriate wound care.