What is the best treatment for a patient with a boil (furuncle) on their buttocks, considering their past medical history, such as diabetes (DM) or immunosuppression?

Treatment of Boils (Furuncles) on the Buttocks

Incision and drainage is the primary and often sufficient treatment for boils on the buttocks, with antibiotics reserved for specific high-risk situations including diabetes, immunosuppression, systemic signs of infection, or extensive surrounding cellulitis. 1

Initial Management for All Patients

Small Boils

• Apply warm, moist compresses several times daily to promote spontaneous drainage 2, 3
• Cover with a dry dressing once drainage occurs 2
• This approach achieves cure rates of 85-90% without antibiotics 2

Large Boils and All Carbuncles

• Perform incision and drainage as the definitive primary treatment 1, 2
• After drainage, cover the wound with a dry dressing rather than packing with gauze—packing adds unnecessary pain without improving outcomes 2, 3
• Drainage alone is likely adequate for simple boils without additional risk factors 1

When to Add Antibiotics

Antibiotics are NOT routinely needed after adequate drainage in otherwise healthy patients. 1, 4 However, antibiotics should be prescribed when ANY of the following conditions exist:

• Diabetes mellitus 1
• Immunosuppression or immunocompromising conditions 1, 4
• Fever or systemic inflammatory response syndrome (SIRS) 1, 4
• Extensive surrounding cellulitis (>2 cm) 1, 4
• Multiple lesions 1, 4
• Rapid progression of infection 1
• Abscess in difficult-to-drain location (face, hand, genitalia) 1
• Lack of response to incision and drainage alone 1
• Associated septic phlebitis 1

Antibiotic Selection

First-Line Oral Options (5-10 days)

When antibiotics are indicated, choose agents active against Staphylococcus aureus with MRSA coverage given high community prevalence 1, 2, 4:

• Trimethoprim-sulfamethoxazole 1, 2, 4
• Doxycycline or minocycline 1, 2, 4
• Clindamycin 1, 2, 4
• Cephalexin or dicloxacillin (if MRSA risk is low) 2, 5

Dosing Considerations

• Dicloxacillin: 250 mg every 6 hours for moderate infections, 500 mg every 6 hours for severe infections; take on empty stomach at least 1 hour before or 2 hours after meals with at least 4 oz of water 5
• Treatment duration should be at least 48 hours after the patient becomes afebrile and asymptomatic 5

Important Caveats

• Do NOT use rifampin as monotherapy or adjunctive therapy 1
• For patients with penicillin allergy, cross-reactivity with cephalosporins occurs in up to 10% of cases 6
• Monitor for Clostridium difficile-associated diarrhea, which can occur up to 2 months after antibiotic use 5, 6

Special Considerations for High-Risk Patients

Diabetic Patients

• Diabetes is a critical host factor that impairs wound healing and increases infection risk 1
• These patients warrant lower threshold for antibiotic therapy even with adequate drainage 1, 4
• Correction of hyperglycemia aids in both eradicating infection and healing the wound 1

Immunosuppressed Patients

• Immunocompromised status (including malnutrition, chronic disease, recent hospitalization) significantly increases risk of complications 1
• Empiric broad-spectrum antibiotic treatment should be initiated even without systemic signs 1
• Consider hospitalization for observation and intravenous antibiotics if infection is moderate or complicated 1

Management of Recurrent Boils

If the patient experiences recurrent episodes despite proper initial treatment 2, 4:

• Culture recurrent abscesses early to identify causative organism and guide antibiotic selection 2, 4
• Evaluate for local anatomic causes: pilonidal cyst, hidradenitis suppurativa, or retained foreign material 4
• Implement decolonization strategy 2, 4:
  • Intranasal mupirocin 2% ointment twice daily for 5 days (repeat monthly if needed) 2, 4, 3
  • Daily chlorhexidine body washes for 5-14 days 2, 4, 3
  • Daily decontamination of personal items (towels, sheets, clothing) 2, 4, 3
• Evaluate household members for S. aureus colonization if ongoing transmission is suspected 2, 4

Hygiene Measures for Prevention

• Cover all draining wounds 4
• Avoid sharing personal items 4
• Use separate towels and washcloths 4, 3
• Clean surfaces that contact bare skin daily 4

Common Pitfalls to Avoid

• Do not prescribe antibiotics for simple boils after adequate drainage in healthy patients—this promotes antibiotic resistance without improving outcomes 1
• Do not pack wounds with gauze after drainage—this increases pain without benefit 2, 3
• Do not perform routine surveillance cultures after decolonization in the absence of active infection 4
• Do not overlook diabetes or immunosuppression—these conditions mandate antibiotic therapy regardless of drainage adequacy 1, 4