What to do for an abscess (collection of pus) in the axilla (armpit)?

Management of Armpit Abscess

Incision and drainage is the definitive treatment for an axillary abscess, and antibiotics are only needed if you have fever, rapid heart rate, or significant surrounding skin infection. 1

Immediate Treatment: Drainage First

• Perform incision and drainage as the cornerstone of treatment - this is the single most important intervention and should not be delayed 1, 2
• Make the incision directly over the abscess to ensure complete drainage 1
• Thoroughly evacuate all pus and probe the cavity to break up any pockets of infection (loculations) 2
• For larger abscesses (>5 cm), use multiple small incisions rather than one long cut to prevent delayed healing and deformity 3, 2
• Simply cover the drained site with a dry sterile dressing - packing with gauze causes more pain without improving healing 1, 4

When to Add Antibiotics

Most patients do NOT need antibiotics after adequate drainage. 1, 2

Skip antibiotics if ALL of the following are present:

• Temperature <38.5°C (101.3°F) 2
• Heart rate <100 beats/minute 2
• White blood cell count <12,000 cells/µL 1, 2
• Surrounding redness extends <5 cm from the abscess 2

Give antibiotics if ANY of these are present:

• Fever >38°C or <36°C 1
• Heart rate >90 beats/minute 1
• Breathing rate >24 breaths/minute 1
• White blood cell count >12,000 or <4,000 cells/µL 1
• Diabetes, immunosuppression, or other immune problems 1, 2
• Extensive cellulitis (spreading skin infection) around the abscess 1, 2

Antibiotic Selection for Axillary Location

For axillary abscesses specifically, use cefoxitin or ampicillin-sulbactam as first-line agents because armpit infections contain mixed bacteria from skin and adjacent areas 2

Alternative oral regimens if outpatient treatment is appropriate:

• Cephalexin 500 mg every 6 hours PLUS metronidazole 500 mg every 8 hours (covers both typical skin bacteria and anaerobes common in the axilla) 2
• Clindamycin 300-450 mg every 6-8 hours if MRSA is suspected or penicillin allergy exists 2, 5
• Treat for 5-7 days based on clinical improvement 1, 2

Culture and Laboratory Testing

• Send the drained pus for culture to identify the bacteria and guide antibiotic adjustments 1, 2
• Obtain blood cultures if you suspect bloodstream infection (high fever, chills, severe illness) 1, 2
• Check complete blood count and inflammatory markers (CRP) if systemic infection is suspected 2

Critical Pitfalls to Avoid

• Never treat with antibiotics alone without drainage - the infection will not resolve and may worsen 2
• Do not attempt needle aspiration - this fails in 75% of cases overall and 90% with MRSA 1
• Do not delay drainage while waiting for imaging or lab results - clinical diagnosis is sufficient for typical cases 3, 6
• Inadequate drainage is the main cause of recurrence (up to 44% recurrence rate) - ensure complete evacuation 3, 6

Follow-Up Care

• Monitor closely for recurrence or failure to heal 6, 2
• If the abscess recurs at the same site, consider underlying causes like hidradenitis suppurativa (chronic inflammatory condition of sweat glands common in armpits) 1, 7
• Patients with recurrent abscesses may benefit from decolonization: intranasal mupirocin twice daily for 5 days, daily chlorhexidine body washes, and daily washing of towels/sheets 1

Special Considerations for Axillary Location

• Axillary abscesses frequently contain anaerobic bacteria (bacteria that grow without oxygen) in addition to Staphylococcus aureus, which is why broader antibiotic coverage is needed compared to abscesses elsewhere 2, 7
• MRSA (methicillin-resistant Staph aureus) can occur in otherwise healthy individuals using shared gym equipment 8
• Rare complications include venous thrombosis (blood clots), so watch for increasing arm swelling or pain 9