What is the treatment for a boil?

Treatment of Boils

The primary treatment for boils (furuncles) is incision and drainage, with systemic antibiotics generally unnecessary unless there are signs of systemic infection or specific risk factors present. 1

What is a Boil?

A boil (furuncle) is an infection of the hair follicle caused by Staphylococcus aureus, where suppuration extends through the dermis into the subcutaneous tissue, forming a small abscess. When infection involves several adjacent follicles, it produces a carbuncle, which is a coalescent inflammatory mass with pus draining from multiple follicular orifices. 1

Treatment Algorithm

Step 1: Initial Management

• For small furuncles: Apply moist heat to promote spontaneous drainage 1
  • Warm compresses applied several times daily
  • This may be sufficient for small boils to rupture and drain on their own

Step 2: Surgical Management

• For large furuncles and all carbuncles: Incision and drainage is the recommended treatment (strong evidence) 1
  • Make an appropriate incision to allow adequate drainage
  • Thoroughly evacuate the pus
  • Probe the cavity to break up loculations
  • Simply cover the surgical site with a dry dressing (most effective approach) 1
  • Avoid packing the wound as one small study found it caused more pain without improving healing 1

Step 3: Determine Need for Antibiotics

Systemic antibiotics are usually unnecessary unless one of the following is present 1:

• Fever or other evidence of systemic infection
• Systemic inflammatory response syndrome (SIRS):
  • Temperature >38°C or <36°C
  • Tachypnea >24 breaths per minute
  • Tachycardia >90 beats per minute
  • White blood cell count >12,000 or <400 cells/µL
• Markedly impaired host defenses
• Extensive surrounding cellulitis
• Multiple lesions

Step 4: If Antibiotics Are Needed

• Choose an antibiotic active against S. aureus 1
• Consider MRSA coverage if:
  • Patient has markedly impaired host defenses
  • Patient has SIRS
  • Local prevalence of MRSA is high

Management of Recurrent Boils

About 10% of patients with a boil will develop a repeat boil within 12 months 2. For recurrent boils:

1. Search for local causes (pilonidal cyst, hidradenitis suppurativa, foreign material) 1
2. Drain and culture early in the course of infection 1
3. Consider a 5-day decolonization regimen: 1
   • Intranasal mupirocin twice daily
   • Daily chlorhexidine washes
   • Daily decontamination of personal items (towels, sheets, clothes)
4. Evaluate adult patients for neutrophil disorders if recurrent abscesses began in early childhood 1

Risk Factors for Recurrence

The following factors are associated with increased risk of recurrent boils: 2

• Obesity
• Diabetes
• Smoking
• Age <30 years
• Prior antibiotic use
• Mechanical stress/friction from tight clothing 3

Important Considerations

• Gram stain and culture of pus from carbuncles and abscesses are recommended but treatment without these studies is reasonable in typical cases 1
• Avoid needle aspiration as it has been shown to be successful in only 25% of cases overall and <10% with MRSA infections 1
• Environmental factors may contribute to boils, including shared steam baths or saunas 4
• Prevention strategies for those with recurrent infections include sitting on towels in shared bathing facilities and avoiding overcrowded bathing situations 4

By following this treatment approach, most boils can be effectively managed with good outcomes and reduced risk of complications or recurrence.