What antibiotics are used to treat an infected pilonidal cyst?

Antibiotic Treatment for Infected Pilonidal Cysts

Primary Treatment Recommendation

Incision and drainage is the definitive treatment for pilonidal cysts, and antibiotics should only be added when systemic signs of infection are present—specifically fever, tachycardia, extensive cellulitis (>5 cm from wound edge), or in immunocompromised patients. 1

When Antibiotics Are Indicated

Antibiotics serve as adjunctive therapy only in specific circumstances:

• Systemic inflammatory response syndrome (SIRS) present: fever, tachycardia, tachypnea, or abnormal white blood cell count 1
• Extensive surrounding cellulitis: erythema and induration extending more than 5 cm from the wound edge 1
• Immunocompromised status 1

Without these features, proceed with incision and drainage alone—antibiotics are unnecessary and may contribute to resistance without improving outcomes. 1

First-Line Antibiotic Regimen

Amoxicillin-clavulanate is the preferred empiric antibiotic for pilonidal infections, providing broad-spectrum coverage against the polymicrobial flora typical of perineal infections. 1 This recommendation aligns with general skin and soft tissue infection guidelines that favor amoxicillin-clavulanate for infections involving the perineum. 2

Duration: 7-10 days for most cases with systemic signs 1

Alternative Regimens

For patients with penicillin allergy or treatment failure:

• Ciprofloxacin plus metronidazole 1
• Ceftriaxone plus metronidazole 2, 1
• Clindamycin 300-450 mg orally three times daily plus trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily) 3

For perineal involvement specifically, cefoxitin or ampicillin-sulbactam are also effective options. 3

Clinical Algorithm

1. Perform incision and drainage as primary intervention 1
2. Assess for systemic signs: measure temperature, heart rate, respiratory rate, and evaluate extent of surrounding erythema 1
3. If systemic signs present: start amoxicillin-clavulanate for 7-10 days 1
4. If penicillin allergy: use ciprofloxacin plus metronidazole or clindamycin plus trimethoprim-sulfamethoxazole 1, 3
5. For recurrent infections: culture the abscess and tailor antibiotics to isolated pathogens for 5-10 days 1

Special Considerations and Pitfalls

Critical pitfall: Inadequate drainage is the most common cause of treatment failure, not antibiotic selection. 3 Antibiotics cannot compensate for poor surgical technique.

Avoid these mistakes:

• Never use amoxicillin or ampicillin monotherapy—poor efficacy and high resistance rates make these inappropriate choices 3
• Beta-lactams alone have shown inferior efficacy compared to combination regimens for perineal skin infections 3
• Reserve fluoroquinolones for cases where other antibiotics cannot be used, as they carry risk of collateral damage and resistance 3

Recurrent Infections

For patients with recurrent pilonidal abscesses:

• Culture the abscess and treat with pathogen-directed antibiotics for 5-10 days 1
• Consider decolonization: 5-day regimen with intranasal mupirocin and chlorhexidine washes 3
• Extend antibiotic duration to 10-14 days for complicated infections based on clinical response 3