What antibiotic and duration of treatment is recommended for an 11-year-old child (pediatric patient) weighing 49kg with a buttock abscess (abscess on the buttock), presenting with swelling, redness, and tenderness to touch?

Treatment of Buttock Abscess in an 11-Year-Old Child

For this 49kg child with a buttock abscess, incision and drainage is the primary treatment, and if antibiotics are indicated based on clinical criteria, clindamycin 10-13 mg/kg/dose every 6-8 hours (not exceeding 40 mg/kg/day) for 5-7 days is the recommended choice. 1, 2

Primary Treatment: Incision and Drainage

• Incision and drainage is the most important therapy for cutaneous abscesses and must be performed regardless of size. 2
• The procedure should include thorough evacuation of pus and probing the cavity to break up loculations. 2
• Simply covering the surgical site with a dry dressing is usually effective, though some clinicians pack it with gauze. 2
• Antibiotics are generally not needed for simple superficial abscesses after adequate drainage. 2

Criteria for Adding Antibiotic Therapy

Antibiotics should be added if any of the following are present: 1, 2

• Temperature >38.5°C 1, 2
• Heart rate >100-110 beats/minute 1, 2
• White blood cell count >12,000 cells/µL 1, 2
• Extensive surrounding cellulitis (erythema extending >5 cm from the abscess) 1
• Multiple sites of infection 1
• Immunocompromised status 1, 2
• Inability to completely drain the abscess 1
• Buttock/perianal location (complex abscess site) 2

Antibiotic Selection and Dosing

For a buttock abscess requiring antibiotics, the location matters significantly:

• Clindamycin is the preferred agent because buttock abscesses involve mixed flora from skin and adjacent perianal areas, and clindamycin covers both Staphylococcus aureus (including community-acquired MRSA) and anaerobic bacteria. 1, 2

Specific dosing for this 49kg child: 1, 3

• Clindamycin: 10-13 mg/kg/dose every 6-8 hours (maximum 40 mg/kg/day)
• For this 49kg child: 490-637 mg per dose every 6-8 hours
• Practical dosing: 600 mg every 8 hours (12.2 mg/kg/dose, well within recommended range)
• Can be given orally if the child can tolerate oral intake 1

Alternative options if clindamycin cannot be used: 1

• TMP-SMX: 4-6 mg/kg/dose (trimethoprim component) every 12 hours (but has limited anaerobic coverage, less ideal for buttock location)
• Amoxicillin-clavulanate: provides broader coverage including anaerobes 4

Duration of Treatment

Treat for 5-7 days based on clinical response. 1, 2

• Most simple abscesses with adequate drainage: 5-7 days 1, 2
• If systemic signs persist or the patient is immunocompromised: up to 7 days 2
• Patients with ongoing signs of infection beyond 7 days warrant diagnostic re-evaluation. 2

Important Clinical Pitfalls to Avoid

Do not rely on antibiotics alone without drainage - this will fail regardless of antibiotic choice. 2

Do not attempt needle aspiration - it has a low success rate of 25% and <10% with MRSA infections. 2

Monitor for Clostridium difficile-associated diarrhea - clindamycin carries this risk, and if significant diarrhea occurs during therapy, the antibiotic should be discontinued. 3

Ensure adequate hydration - clindamycin capsules should be taken with a full glass of water to avoid esophageal irritation. 3

Watch for treatment failure indicators: 2

• Persistent fever beyond 48-72 hours after drainage
• Worsening erythema or swelling
• Development of new lesions
• Systemic toxicity

Special Considerations for Buttock Location

• Buttock/perianal abscesses are considered complex abscesses due to polymicrobial flora including anaerobes from adjacent bowel flora. 1, 2
• These infections typically involve both aerobic (Staphylococcus aureus) and anaerobic organisms, making clindamycin's dual coverage particularly valuable. 1
• Broader spectrum coverage with agents like cefoxitin or ampicillin-sulbactam may be considered for axillary or perianal locations if the infection is severe or not responding to initial therapy. 2