What is the first-line treatment for furuncles (boils) located in the axillary region?

First-line Treatment for Axillary Boils (Furuncles)

Incision and drainage is the recommended first-line treatment for boils (furuncles) in the axillary region, with systemic antibiotics generally unnecessary unless there are signs of systemic infection or specific risk factors. 1

Understanding Axillary Furuncles

• Furuncles (boils) are infections of hair follicles caused primarily by Staphylococcus aureus, where suppuration extends through the dermis into subcutaneous tissue, forming a small abscess 1
• Axillary location is common due to hair follicles, moisture, friction, and proximity to lymph nodes 1
• Clinically present as inflammatory nodules with overlying pustules through which hair emerges 1

Treatment Algorithm

Primary Treatment:

1. Small furuncles:

   • Application of moist heat to promote spontaneous drainage 1
   • Warm compresses applied several times daily can facilitate drainage 1

2. Large furuncles:

   • Incision and drainage (I&D) is the definitive treatment 1
   • Procedure involves:
     • Making an incision over the fluctuant area
     • Thorough evacuation of pus
     • Probing the cavity to break up loculations 1
   • Post-procedure wound care:
     • Simply covering the surgical site with a dry dressing is usually most effective 1
     • Packing is not necessary and may cause more pain without improving healing 1

Antibiotic Therapy:

• Systemic antibiotics are usually unnecessary for uncomplicated furuncles after adequate I&D 1

• Antibiotics should be added only in specific circumstances:

  • Presence of systemic inflammatory response syndrome (SIRS) 1
  • Fever or other evidence of systemic infection 1
  • Extensive surrounding cellulitis 1
  • Markedly impaired host defenses 1
  • Multiple lesions 1

• When antibiotics are indicated, they should target S. aureus:

  • For methicillin-susceptible S. aureus: oral penicillinase-resistant penicillins or first-generation cephalosporins 1
  • For suspected MRSA: doxycycline, clindamycin, or trimethoprim-sulfamethoxazole 1

Management of Recurrent Furuncles

For patients with recurrent axillary boils:

1. Evaluate for underlying causes:

   • Search for local factors such as hidradenitis suppurativa or foreign material 1, 2
   • Consider nasal carriage of S. aureus (present in ~60% of recurrent cases) 3

2. Decolonization measures:

   • 5-day regimen of:
     • Intranasal mupirocin twice daily
     • Daily chlorhexidine washes
     • Daily decontamination of personal items (towels, sheets, clothes) 1, 3

3. Hygiene measures:

   • Bathing with antibacterial soaps like chlorhexidine 1
   • Thorough laundering of clothing, towels, and bedding 1
   • Separate use of towels and washcloths 1
   • Avoid tight-fitting clothing that may cause friction in the axillary area 2

Important Caveats and Pitfalls

• Avoid needle aspiration of axillary abscesses as it has low success rates (25% overall, <10% with MRSA) 1
• Culture is not routinely needed for typical, isolated furuncles but should be obtained in recurrent cases or treatment failures 1
• Do not confuse furuncles with hidradenitis suppurativa, which is a chronic inflammatory condition of apocrine glands that may present similarly in the axilla 2
• Carbuncles (coalescent inflammatory mass with multiple draining points) require more aggressive management than simple furuncles 1
• Avoid antibiotic overuse for simple furuncles that have been adequately drained, as this contributes to antimicrobial resistance 1