What is the treatment for an infected boil?

Treatment of Infected Boils

Incision and drainage is the primary and definitive treatment for infected boils, and antibiotics are generally not necessary for simple boils that can be adequately drained. 1

Primary Treatment Approach

Incision and Drainage (I&D)

• I&D is the recommended treatment for large furuncles and all carbuncles 1
• The procedure involves:
  • Making an incision to access the abscess 1
  • Thorough evacuation of pus 1
  • Probing the cavity to break up loculations 1
  • Covering the surgical site with a dry dressing (packing is NOT recommended as it causes more pain without improving healing) 1
• Most simple abscesses can be safely managed in the ambulatory office with I&D 2

Small Boils

• For small furuncles, application of moist heat is satisfactory and may promote spontaneous drainage 1
• Warm compresses can help bring the boil to a head, allowing it to drain naturally 1

When Antibiotics ARE Indicated

Antibiotics should be reserved for specific clinical scenarios 1:

• Presence of systemic inflammatory response syndrome (SIRS): temperature >38°C or <36°C, tachypnea >24 breaths per minute, tachycardia >90 beats per minute, or white blood cell count >12,000 or <4,000 cells/μL 1
• Extensive surrounding cellulitis 1
• Markedly impaired host defenses (immunocompromised patients) 1
• Severe systemic manifestations such as high fever 1

Antibiotic Selection When Needed

When antibiotics are indicated, empiric therapy should target Gram-positive bacteria, particularly Staphylococcus aureus 3:

• Dicloxacillin (for methicillin-sensitive S. aureus): Adults take 150-300 mg every 6 hours for serious infections, or 300-450 mg every 6 hours for more severe infections, taken one hour before meals or two hours after eating 4
• Clindamycin (for MRSA or penicillin-allergic patients): Adults take 150-300 mg every 6 hours for serious infections, or 300-450 mg every 6 hours for more severe infections, with a full glass of water 5
• Empiric therapy for community-acquired MRSA (CA-MRSA) should be recommended for patients at risk for CA-MRSA or who do not respond to first-line therapy 3

Management of Recurrent Boils

For patients with recurrent boils, implement decolonization measures 1:

• Daily chlorhexidine washes to reduce bacterial colonization 1
• Daily decontamination of personal items such as towels, sheets, and clothes 1
• Thorough laundering of clothing, towels, and bed wear 1
• Separate use of towels and washcloths 1

Risk Factors for Recurrence

• Obesity, diabetes, age <30 years, smoking, and prior antibiotic use are all associated with repeat consultation for boils 6
• Approximately 10% of patients develop a repeat boil within 12 months 6

Special Considerations and Workup

• For recurrent abscesses at the same site, search for local causes such as pilonidal cyst, hidradenitis suppurativa, or foreign material 1
• Adult patients with recurrent abscesses that began in early childhood should be evaluated for neutrophil disorders 1
• Gram stain and culture of pus from carbuncles and abscesses are recommended, but treatment without these studies is reasonable in typical cases 1

Critical Pitfalls to Avoid

• Do NOT pack the wound with gauze - this causes more pain and does not improve healing compared to simply covering the incision site with sterile gauze 1
• Do NOT attempt ultrasonographically guided needle aspiration - this has only 25% success rate overall and <10% success with MRSA infections 1
• Do NOT lance boils at home with non-sterile instruments - this can lead to severe invasive infections including osteomyelitis, subperiosteal abscess, and pyomyositis 7
• Do NOT routinely prescribe antibiotics for uncomplicated boils that can be managed with I&D alone 1, 2
• Wound culture and antibiotics do not improve healing in simple abscesses 2