Treatment of Injection Site Infections

Diagnosis and Assessment

Injection site infections typically present with local signs including pain, tenderness, swelling, redness, and induration, according to the Infectious Diseases Society of America 1, 2
Evaluate for systemic signs that would indicate need for antibiotics: temperature >38.5°C, heart rate >110 beats/minute, white blood cell count >12,000/μL, or erythema extending >5 cm from the wound edge, as recommended by the Infectious Diseases Society of America 3, 2
Gram stain and culture of pus from abscesses are recommended to guide targeted antimicrobial therapy, though treatment without these studies is reasonable in typical cases, according to the Infectious Diseases Society of America 4

Incision and drainage is the cornerstone of treatment for injection site abscesses and infections, as recommended by the Infectious Diseases Society of America 1, 4, 2
For all incisional infections, open the site, evacuate infected material, and continue dressing changes until the wound heals by secondary intention, according to the Infectious Diseases Society of America 2
Antibiotics are NOT routinely indicated for uncomplicated injection site infections after adequate drainage, as stated by the Infectious Diseases Society of America 3, 2

Systemic signs of infection (fever >38.5°C, tachycardia >110 beats/minute) indicate the need for antibiotics, according to the Infectious Diseases Society of America 3, 2
Erythema extending >5 cm from the injection site also indicates the need for antibiotics, as recommended by the Infectious Diseases Society of America 3, 2
Immunocompromised patients may require antibiotics, according to the Infectious Diseases Society of America 2
Failure to improve after incision and drainage may also indicate the need for antibiotics, as stated by the Infectious Diseases Society of America 1, 3

For methicillin-susceptible S. aureus (MSSA), first-line treatment is Cephalexin 500 mg orally four times daily for 5-7 days, as recommended by the Infectious Diseases Society of America 1, 3
For suspected or confirmed methicillin-resistant S. aureus (MRSA), treatment options include Trimethoprim-sulfamethoxazole (SMX-TMP), Doxycycline, or Clindamycin, according to the Infectious Diseases Society of America 1

For injection sites near axilla or perineum, broader coverage may be needed with metronidazole plus either ciprofloxacin, levofloxacin, or ceftriaxone, as recommended by the Infectious Diseases Society of America 5, 2
For injection site infections following procedures involving intestinal or genital tracts, consider broader coverage with agents active against gram-negative bacteria and anaerobes, according to the Infectious Diseases Society of America 3
If antibiotics are needed, a short course (5-7 days) is typically sufficient after adequate drainage, as stated by the Infectious Diseases Society of America 5, 2

For patients with recurrent injection site infections (3-4 episodes per year), prophylactic antibiotics may be considered, according to the Infectious Diseases Society of America 5
Options include oral penicillin or erythromycin twice daily for 4-52 weeks, or intramuscular benzathine penicillin every 2-4 weeks, as recommended by the Infectious Diseases Society of America 5
Identify and treat predisposing conditions such as edema, obesity, eczema, and other skin conditions, according to the Infectious Diseases Society of America 5