What is the treatment for a furuncle (boil)?

Treatment of Furuncles (Boils)

For small furuncles, apply moist heat to promote spontaneous drainage; for large furuncles and all carbuncles, incision and drainage is mandatory, with systemic antibiotics reserved only for cases with fever, extensive surrounding cellulitis, or systemic signs of infection. 1

Initial Treatment Algorithm

Small Furuncles

• Apply moist heat (warm compresses) to promote spontaneous drainage 2, 1
• This conservative approach is satisfactory for small lesions without systemic involvement 2
• No antibiotics are needed for uncomplicated small furuncles 1

Large Furuncles and All Carbuncles

• Incision and drainage is the cornerstone of treatment and is mandatory for all large furuncles and carbuncles 2, 1, 3
• After drainage, cover the surgical site with a dry dressing rather than packing with gauze 1
• Thoroughly evacuate pus and probe to break up any loculations 3

When to Add Systemic Antibiotics

Antibiotics are usually unnecessary after adequate drainage unless specific conditions are present 2, 1. Add systemic antibiotics only when:

• Fever or systemic signs of infection (SIRS criteria: temperature >38°C or <36°C, tachycardia >90 bpm, tachypnea >24/min, WBC >12,000 or <4,000 cells/μL) 1, 4
• Extensive surrounding cellulitis 2, 1, 4
• Multiple lesions present 1, 4
• Markedly impaired host defenses (immunosuppression, diabetes) 1, 4

Antibiotic Selection When Indicated

Choose an agent active against Staphylococcus aureus: 1

• For methicillin-susceptible S. aureus (MSSA): Dicloxacillin 500 mg every 6 hours orally 4
• For suspected or confirmed MRSA (high-prevalence areas or risk factors): Clindamycin 300-450 mg every 6 hours orally 1, 4
• Duration: 5-10 days for mild to moderate infections 4

Common pitfall: Do not treat furuncles or carbuncles with antibiotics alone without drainage—this approach will fail 3

Management of Recurrent Furunculosis

Recurrent furunculosis affects individuals who are often nasal carriers of S. aureus (20-40% of the general population carries the organism) 2. A structured decolonization approach is essential:

Decolonization Protocol

• Intranasal mupirocin ointment twice daily for the first 5 days of each month (reduces recurrences by ~50%) 2, 1
• Daily chlorhexidine body washes during decolonization periods 1
• For more aggressive treatment: Oral clindamycin 150 mg daily for 3 months decreases subsequent infections by ~80% for susceptible strains 2

Environmental and Hygiene Measures

• Thoroughly launder clothing, towels, and bed linens 2, 1
• Use separate towels and washcloths to prevent transmission 2, 1
• Bathe with antibacterial soaps such as chlorhexidine 2
• Decontaminate personal items daily during active infection 1, 4

Family and Close Contact Management

• Screen and treat household members who may be colonized carriers, as outbreaks commonly occur in families and close-contact settings (prisons, sports teams) 2, 5
• Inadequate personal hygiene and exposure to others with furuncles are important predisposing factors 2

Important caveat: Even with optimal decolonization (mupirocin), recurrence reduction is only about 50%, so patient expectations should be managed appropriately 2. The most effective regimen for recurrent cases caused by susceptible organisms is the 3-month clindamycin course 2.