What antibiotics are used to treat infected pilonidal cysts?

Antibiotic Management for Infected Pilonidal Cysts

For infected pilonidal cysts, clindamycin 300-450 mg orally three times daily plus trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily) is the recommended first-line antibiotic regimen, but only as an adjunct to incision and drainage, which remains the primary treatment. 1

Primary Treatment Principle

• Incision and drainage is the cornerstone of treatment for inflamed pilonidal cysts and abscesses, with antibiotics serving only as adjunctive therapy 2, 1
• Antibiotics should be added based on the presence of systemic inflammatory response syndrome (SIRS): temperature >38°C or <36°C, tachypnea >24 breaths/minute, tachycardia >90 beats/minute, or white blood cell count >12,000 or <4,000 cells/µL 2, 1
• Failure to adequately drain the abscess is the most common reason for treatment failure, not antibiotic selection 1, 3

First-Line Antibiotic Regimens

For perineal/sacrococcygeal infections (pilonidal cysts):

• Clindamycin 300-450 mg orally three times daily PLUS trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily) 1
• Alternative: Cefoxitin or ampicillin-sulbactam for infections involving the perineum 2, 1, 3

For patients with penicillin allergy:

• Clindamycin plus ciprofloxacin 1

For uncomplicated purulent drainage without surrounding cellulitis:

• Cephalexin 500 mg orally four times daily may be considered after adequate drainage 3

Duration of Therapy

• 5-7 days for most uncomplicated cases following adequate drainage 1, 3
• 10-14 days for severe or complicated infections based on clinical response 1, 3

Antibiotics to Avoid

• Do NOT use amoxicillin or ampicillin monotherapy due to poor efficacy and high resistance rates 1
• Beta-lactams generally have inferior efficacy and more adverse effects compared to other antimicrobials for skin infections 1, 3
• Fluoroquinolones should be reserved for cases where other antibiotics cannot be used 1

Management of Recurrent Infections

• Culture the abscess and treat with antibiotics active against the isolated pathogen 2
• Consider a 5-day decolonization regimen: intranasal mupirocin twice daily PLUS daily chlorhexidine washes PLUS daily decontamination of personal items (towels, sheets, clothes) 2, 1
• Search for local causes such as retained foreign material or hidradenitis suppurativa 2

Critical Clinical Pitfalls

• Never rely on antibiotics alone without drainage - this is the primary cause of treatment failure 1, 3
• Pilonidal cysts in the perineal region require coverage for gut flora, not just typical skin flora, hence the need for broader coverage than simple skin abscesses 2, 1
• Obtain cultures from recurrent abscesses early in the course to guide targeted therapy 2
• The location of pilonidal cysts (perineum/sacrococcygeal area) necessitates coverage for both aerobic and anaerobic organisms, which is why combination therapy or agents like ampicillin-sulbactam are preferred 2, 1