Treatment of Boils (Furuncles)
Incision and drainage is the primary treatment for boils, and oral antibiotics should only be added when systemic signs of infection are present (fever, tachycardia, elevated white blood cell count) or in patients with significantly impaired immune function. 1
Primary Treatment Approach
- Incision and drainage alone is sufficient for most boils without the need for antibiotics 1
- Small furuncles may rupture and drain spontaneously with moist heat application, but large furuncles and all carbuncles require incision and drainage 1
- After drainage, simply covering the wound with a dry sterile dressing is the most effective approach—packing the wound causes more pain without improving healing 1
When to Add Oral Antibiotics
Antibiotics directed against Staphylococcus aureus should be added to incision and drainage based on specific clinical criteria 1:
Indications for antibiotic therapy:
Presence of SIRS (Systemic Inflammatory Response Syndrome) 1:
- 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 (immunocompromised patients) 1
Carbuncles (coalescent infections involving multiple adjacent follicles, especially on the back of the neck in diabetic patients) 1
Antibiotic Selection
For MRSA coverage (when indicated):
- Clindamycin
- Doxycycline
- Trimethoprim-sulfamethoxazole (SMX-TMP) 1
For methicillin-susceptible infections:
- Oral penicillinase-resistant penicillin (e.g., dicloxacillin)
- First-generation cephalosporins (e.g., cephalexin) 1
Important caveat: Most staphylococcal isolates from skin abscesses are now community-acquired MRSA, so empiric MRSA coverage is typically warranted when antibiotics are indicated 1
Safety considerations:
- Sulfonamide antibiotics and cephalosporins carry the highest risk of serious cutaneous adverse drug reactions compared to macrolides 2
- When clinically appropriate, consider lower-risk alternatives, though efficacy for the specific pathogen must take priority 2
Culture Recommendations
- Gram stain and culture of pus are recommended for carbuncles and abscesses, though treatment without these studies is reasonable in typical cases 1
- Culture is particularly important for recurrent abscesses to guide targeted therapy 1
Recurrent Boils
For patients with recurrent abscesses 1:
- Drain and culture early in the infection course
- Treat with a 5- to 10-day course of an antibiotic active against the isolated pathogen
- Consider decolonization with intranasal mupirocin twice daily for 5 days, daily chlorhexidine washes, and decontamination of personal items
- Search for local causes such as pilonidal cysts, hidradenitis suppurativa, or foreign material
Evidence Quality Note
A Cochrane review found no significant differences in clinical cure rates between various oral antibiotics for boils, though most studies had methodological limitations and did not consistently report antibiotic sensitivity data 3. This reinforces that the choice to use antibiotics at all—rather than which specific antibiotic—is the critical clinical decision, with incision and drainage remaining the cornerstone of treatment 1.