Treatment of Actinomyces neuii in Skin Abscess on Neck
The primary treatment for Actinomyces neuii skin abscess on the neck is incision and drainage followed by a 5-10 day course of amoxicillin-clavulanic acid (875/125 mg twice daily). 1
Diagnostic Approach
- Obtain wound culture during incision and drainage to confirm Actinomyces neuii infection
- Assess for systemic inflammatory response syndrome (SIRS):
- Temperature >38°C or <36°C
- Tachypnea >24 breaths per minute
- Tachycardia >90 beats per minute
- White blood cell count >12,000 or <400 cells/μL 2
Treatment Algorithm
Step 1: Surgical Management
- Incision and drainage is the cornerstone of treatment for all abscesses 1
- Complete evacuation of purulent material is essential
- Consider more extensive surgical debridement if the abscess is large or has extensive surrounding cellulitis
Step 2: Antibiotic Therapy
- First-line: Amoxicillin-clavulanic acid 875/125 mg PO twice daily for 5-10 days 1
- For penicillin-allergic patients (non-anaphylactic): Cephalexin 500 mg four times daily 1
- For penicillin-allergic patients (anaphylactic): Clindamycin 300-450 mg four times daily 1
- For severe infections with SIRS: Consider IV therapy with vancomycin plus piperacillin-tazobactam 2, 1
Step 3: Duration of Therapy
- Standard course: 5-10 days 1
- Extended therapy (up to several weeks) may be needed for:
- Immunocompromised patients
- Extensive infection
- Slow clinical response 1
Antibiotic Considerations
- A. neuii is almost uniformly susceptible to β-lactam antibiotics (with or without β-lactamase inhibitors), carbapenems, tetracyclines, and vancomycin 3
- Avoid metronidazole as Actinomyces species are uniformly resistant 3
- Unlike typical Actinomyces species, A. neuii grows aerobically and doesn't form branching filaments 4
Post-Treatment Care
- Cover the surgical site with a dry dressing 1
- Warm soaks can promote drainage 1
- Re-evaluate in 48-72 hours to assess healing progress 1
- Monitor for complications:
- Spread of infection to adjacent structures
- Systemic infection
- Recurrence
- Fistula formation 1
Special Considerations
- A. neuii is an unusual pathogen that differs from other Actinomyces species in its aerobic growth and microscopic morphology 4
- Most A. neuii infections are abscesses or infected atheromas, with generally good prognosis following antibiotic and surgical treatment 4
- For recurrent abscesses, search for local causes such as pilonidal cyst, hidradenitis suppurativa, or foreign material 2
- Consider a 5-day decolonization regimen for recurrent infections, including intranasal mupirocin, daily chlorhexidine washes, and decontamination of personal items 2
The combination of surgical drainage and appropriate antibiotic therapy typically results in favorable outcomes for patients with A. neuii skin abscesses 5.