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, perform incision and drainage—systemic antibiotics are usually unnecessary unless fever, extensive cellulitis, or systemic signs are present. 1, 2

Initial Treatment Based on Size

Small Furuncles

• Apply moist heat to promote spontaneous drainage 1, 2
• This conservative approach is satisfactory for small lesions without systemic involvement 1

Large Furuncles and All Carbuncles

• Incision and drainage is mandatory and the cornerstone of treatment 1, 2, 3
• After drainage, cover the surgical site with a dry dressing rather than packing with gauze 2, 4
• Thoroughly evacuate pus and probe to break up loculations 3

When to Add Systemic Antibiotics

Antibiotics are usually unnecessary after adequate drainage unless specific conditions are present 1, 2:

• Fever or other evidence of systemic infection 2, 4
• Extensive surrounding cellulitis 1, 2, 4
• Systemic inflammatory response syndrome (SIRS) with temperature >38°C or <36°C, tachypnea >24 breaths/min, tachycardia >90 bpm, or WBC >12,000 or <4,000 cells/μL 2, 4
• Markedly impaired host defenses (diabetes, immunosuppression) 2, 4
• Multiple lesions 2, 4

Antibiotic Selection When Indicated

For methicillin-susceptible S. aureus (MSSA):

• Dicloxacillin 500 mg every 6 hours orally 4

For methicillin-resistant S. aureus (MRSA) or high-prevalence areas:

• Clindamycin 300-450 mg every 6 hours orally 2, 4

Duration: 5-10 days for mild to moderate infections 4

Management of Recurrent Furunculosis

Decolonization Strategies

The major method of controlling recurrent furunculosis is eradicating staphylococcal carriage 1:

• Intranasal mupirocin ointment twice daily for the first 5 days each month reduces recurrences by approximately 50% 1, 2
• Daily chlorhexidine washes are also effective 2, 4
• Oral clindamycin 150 mg daily for 3 months is probably the best program for recurrent furunculosis caused by susceptible S. aureus, decreasing subsequent infections by approximately 80% 1

Environmental Decontamination

Control of outbreaks may require 1, 2:

• Bathing with antibacterial soaps such as chlorhexidine 1, 2
• Thorough laundering of clothing, towels, and bed linens 1, 2
• Separate use of towels and washcloths 1, 2
• Daily decontamination of personal items 2, 4

Evaluation of Carriers

• The prevalence of nasal staphylococcal colonization in the general population is 20-40% 1
• Evaluate for predisposing factors such as nasal colonization with S. aureus in the anterior nares or perineum 1, 2
• Culture swabs from the patient, family members, and close contacts are mandatory in recurrent cases to identify and control the chain of infection 5

Common Pitfalls to Avoid

• Do not treat furuncles or carbuncles with antibiotics alone without drainage—this approach will fail 3
• Do not confuse furuncles/carbuncles with cellulitis—cellulitis has no pus collection and requires antibiotics as primary treatment, not incision and drainage 3
• Consider obtaining culture of pus to guide antibiotic therapy if systemic treatment is needed, especially with multiple lesions or recurrent infections 3, 4
• Have a lower threshold for initiating systemic antibiotics in patients with diabetes or immunosuppression 4