How do I treat an open boil?

Treatment of an Open Boil (Furuncle)

Incision and drainage is the primary and definitive treatment for boils, and antibiotics are typically unnecessary unless specific high-risk features are present. 1

Primary Treatment: Incision and Drainage

• The most important therapy is to open the boil, evacuate the infected material, and continue dressing changes until the wound heals by secondary intention. 2
• Simply covering the surgical site with a dry dressing is usually the most effective treatment of the wound after drainage. 2
• Obtain Gram stain and culture of the pus during drainage, though treatment without these studies is reasonable in typical cases. 1
• For large boils that are troublesome or interfere with function, pierce them with a sterile needle to release fluid while leaving the blister roof in place as a biological dressing. 2

When Antibiotics Are NOT Needed

• If there is <5 cm of erythema and induration around the boil, and the patient has minimal systemic signs (temperature <38.5°C, WBC count <12,000 cells/µL, pulse <100 beats/minute), antibiotics are unnecessary. 2
• Studies of subcutaneous abscesses found little or no benefit for antibiotics when combined with drainage. 2
• Incision and drainage of superficial abscesses rarely causes bacteremia, so prophylactic antibiotics are not recommended. 2

When to Add Antibiotics to Incision and Drainage

Add antibiotics directed against S. aureus when ANY of the following are present: 1

• Temperature >38.5°C or heart rate >110 beats/minute 2, 1
• Erythema extending >5 cm beyond the wound margins 2, 1
• Systemic inflammatory response syndrome (SIRS) 1
• Severe or extensive disease with rapid progression 1
• Markedly impaired host defenses or immunocompromised status 1
• Extremes of age 1
• Difficult to drain locations 1
• Associated septic phlebitis 1
• Lack of response to incision and drainage alone 1

Antibiotic Selection When Indicated

• Empirical coverage for community-acquired MRSA (CA-MRSA) is recommended pending culture results. 1
• Treatment options include: clindamycin, trimethoprim-sulfamethoxazole (TMP-SMX), tetracyclines (doxycycline or minocycline), or linezolid. 1
• Adjust antibiotic therapy based on culture results. 3
• Do NOT use rifampin as a single agent or adjunctive therapy for boils. 1

Duration of Treatment

• When antibiotics are used, prescribe 5 to 10 days of therapy based on clinical response. 1
• Evaluate for clinical improvement (decreased pain and swelling) within 48-72 hours after treatment. 3

Wound Care After Drainage

• After drainage, apply a bland emollient such as 50% white soft paraffin and 50% liquid paraffin to support barrier function and encourage re-epithelialization. 2
• Alternatively, apply a small amount of topical antibiotic ointment (bacitracin or triple antibiotic) 1 to 3 times daily and cover with a sterile bandage. 4, 5
• For extensive areas of erosion, antiseptics such as potassium permanganate baths or antiseptic-containing bath oils may be used for a few days to dry lesions and prevent infection. 2
• Painful areas may be covered with a low-adhesion dressing such as Mepitel or Atrauman held in place with soft elasticated viscose. 2

Management of Recurrent Boils

• Search for local causes such as pilonidal cyst, hidradenitis suppurativa, or foreign material at sites of recurrent infection. 1
• Culture recurrent abscesses early in the course of infection. 1
• Consider a 5-day decolonization regimen including intranasal mupirocin, daily chlorhexidine washes, and daily decontamination of personal items for patients with recurrent S. aureus boils. 1
• Treat with a 5- to 10-day course of an antibiotic active against the isolated pathogen. 1
• Risk factors for recurrence include obesity, diabetes, age <30 years, smoking, and prior antibiotic use. 6

Critical Pitfalls to Avoid

• Do not routinely prescribe antibiotics without incision and drainage—antibiotics without drainage are ineffective as the primary treatment. 1
• Avoid ultrasonographically guided needle aspiration, as it was successful in only 25% of cases overall and <10% with MRSA infections. 1
• Never attempt home lancing with non-sterile instruments (e.g., hot needles), as this can lead to severe invasive infection including osteomyelitis and sepsis. 7