What is the medical term for small, pus-draining boils in the axillae?

Medical Term for Small Boils in Armpits that Drain Pus

The medical term for small, pus-draining boils in the armpits is "furuncles" (or "boils"), which are infections of hair follicles caused primarily by Staphylococcus aureus. 1

Understanding the Condition

Furuncles are distinct from simple folliculitis because the infection extends deeper—through the dermis into subcutaneous tissue where a small abscess forms 1. Each lesion presents as:

• An inflammatory nodule
• An overlying pustule through which hair emerges
• Pus drainage when the lesion ruptures or is drained

Key Differential Diagnosis

However, if these lesions are recurrent, chronic, and involve multiple nodules, abscesses, and draining sinus tracts specifically in the axillae, you must consider hidradenitis suppurativa (HS) 2, 3, 4. This is a critical distinction because:

• Furuncles are acute infections of individual hair follicles, typically caused by S. aureus
• Hidradenitis suppurativa is a chronic inflammatory disease affecting apocrine gland-bearing areas (axillae, groin, inframammary regions) with recurrent nodules, abscesses, and tunnel formation 3, 4

Treatment Approach

For Simple Furuncles:

Small furuncles: Apply moist heat to promote drainage 1

Large furuncles: Require incision and drainage 5

Antibiotics are NOT routinely needed unless 5:

• Extensive surrounding cellulitis present
• Fever or systemic inflammatory response syndrome (SIRS) present (temperature >38°C or <36°C, tachycardia >90 bpm, tachypnea >24 breaths/min, WBC >12,000 or <4,000 cells/µL)
• Multiple lesions
• Severely impaired host defenses

For Recurrent Furuncles (Furunculosis):

Culture the lesions to identify the pathogen 5

Decolonization regimen 1, 5:

• Intranasal mupirocin ointment twice daily for first 5 days each month (reduces recurrences by ~50%)
• OR oral clindamycin 150 mg daily for 3 months (decreases infections by ~80% for susceptible S. aureus)
• Consider chlorhexidine body washes
• Launder clothing, towels, and bedding thoroughly

Critical Pitfalls to Avoid

1. Don't miss hidradenitis suppurativa: If lesions are recurrent over 6 months with ≥2 episodes, occur in typical flexural locations (axillae, groin, perineum, inframammary), and include nodules, sinus tracts, or bridging scars—this is HS, not simple furunculosis 2, 6

2. Don't overuse antibiotics: Systemic antibiotics are unnecessary for uncomplicated furuncles after adequate drainage 5

3. Don't culture inflamed epidermoid cysts: These contain normal skin flora and inflammation occurs from cyst wall rupture, not infection 1

4. Screen for MRSA: In the current era, consider MRSA coverage if antibiotics are needed, especially with SIRS, immunocompromise, or failed initial therapy 5