Home Specimen Collection for Draining Axillary Abscess
Send the patient a sterile specimen collection container with instructions to collect purulent drainage directly from the abscess into the container, ideally after cleansing the surrounding skin with soap and water, then refrigerate and return it within 24 hours for culture.
Practical Collection Method
The patient should collect the specimen themselves using a sterile container sent by mail or courier. 1 While guidelines emphasize that deep tissue specimens obtained by curettage or biopsy provide the most accurate results, this requires in-person evaluation. 2 For remote collection, the next best option is having the patient collect purulent drainage directly.
Step-by-Step Instructions for the Patient
- Cleanse the area around the draining abscess with soap and water (not antiseptic, which may kill bacteria and affect culture results) 2
- Express purulent material directly into the sterile container provided, avoiding contact with surrounding skin 1
- Collect at least 1-2 mL of purulent drainage if possible 1
- Seal the container immediately and label with patient name, date, and time of collection 1
- Refrigerate the specimen until it can be returned to the laboratory 1
- Return within 24 hours for optimal culture results 1
Why This Matters for Treatment
Culture results are critical because the patient is already on doxycycline, which may not adequately cover the causative organism. 1, 3 Axillary abscesses are commonly caused by Staphylococcus aureus (including MRSA), but can also harbor anaerobic bacteria or other pathogens. 4, 5 A case report documented MRSA axillary abscess in a college athlete that was resistant to initial cephalexin therapy but susceptible to trimethoprim-sulfamethoxazole. 4
The Infectious Diseases Society of America recommends obtaining cultures before starting antibiotics, particularly in patients with recent antibiotic exposure, to guide definitive therapy. 3 Since this patient is already on doxycycline, culture results become even more important to determine if the current antibiotic is appropriate or if a change is needed. 3
Important Caveats
- Swab specimens are less accurate than aspirated pus or tissue samples 1, 2, but in this remote scenario, direct collection of purulent drainage is the most practical option
- Request both aerobic and anaerobic cultures since anaerobic bacteria are found in approximately 23% of axillary abscesses 5
- The specimen quality will be suboptimal compared to in-person collection, but it's better than no culture, especially given the patient's current antibiotic therapy 3
- If the patient cannot produce adequate purulent drainage, consider having them use a sterile swab moistened with sterile saline to collect material from the abscess opening, though this is less ideal 1
Clinical Decision Point
If the patient shows signs of systemic infection (fever, chills, spreading cellulitis), worsening despite doxycycline, or has risk factors for MRSA or resistant organisms, they should be seen urgently rather than relying on home specimen collection. 1, 2 Doxycycline alone may be inadequate for complicated skin and soft tissue infections, particularly if MRSA or anaerobes are involved. 1