What is the recommended treatment for an infected pilonidal cyst with purulent sanguineous drainage and tenderness, considering cephalexin (cephalexin) as a potential antibiotic option?

Management of Infected Pilonidal Cyst with Purulent Drainage

Cephalexin is an appropriate first-line antibiotic choice for an infected pilonidal cyst with purulent drainage, but it should be used as an adjunct to incision and drainage, which remains the cornerstone of treatment. 1, 2

Primary Management Approach

• Incision and drainage is the recommended primary treatment for inflamed pilonidal cysts and abscesses 1, 2
• Systemic antibiotics should be added based on the presence or absence of systemic inflammatory response syndrome (SIRS) such as fever, tachypnea, tachycardia, or abnormal white blood cell count 1, 3
• A recurrent abscess at a site of previous infection should prompt a search for local causes such as a pilonidal cyst 1

Antibiotic Selection

• For the described case with purulent drainage but no surrounding skin inflammation:

  • Cephalexin (first-generation cephalosporin) is an appropriate choice for empiric therapy 1
  • Typical dosing is 500 mg orally four times daily for 5-7 days 2
  • Cephalexin has demonstrated similar efficacy to other antibiotics for uncomplicated skin and soft tissue infections 4

• Alternative first-line options if cephalexin is not suitable:

  • Clindamycin 300-450 mg orally three times daily plus trimethoprim-sulfamethoxazole (1-2 double-strength tablets twice daily) 2, 3
  • For patients with penicillin allergy, clindamycin plus ciprofloxacin is recommended 3

Special Considerations

• For infections involving the perineum/sacrococcygeal area, cefoxitin and ampicillin-sulbactam are also considered effective options 1
• Gram stain and culture of pus from abscesses are recommended, but treatment without these studies is reasonable in typical cases 1
• The absence of surrounding skin inflammation in this case suggests a more localized infection, which may respond well to drainage plus targeted antibiotic therapy 1, 5

Duration of Therapy

• For most uncomplicated cases, 5-7 days of antibiotic therapy is sufficient following adequate drainage 2
• For more severe or complicated infections, treatment may need to be extended to 10-14 days based on clinical response 2

Common Pitfalls and Caveats

• Failure to properly drain the abscess is the most common reason for treatment failure, not antibiotic selection 2, 6
• Beta-lactams (like cephalexin) have shown inferior efficacy in some studies compared to other antimicrobials for skin infections, but remain appropriate for pilonidal infections when combined with proper drainage 3
• For recurrent infections, consider a 5-day decolonization regimen with intranasal mupirocin and chlorhexidine washes 3
• Definitive treatment may require more extensive surgical intervention if recurrences occur despite appropriate antibiotic therapy and drainage 5, 7