What is the treatment for a Staphylococcus (Staph) infection of the finger?

Treatment of Staphylococcus Infection of the Finger

For a staph infection of the finger, incision and drainage is the primary treatment if purulent material is present, followed by oral antibiotics for 7 days with dicloxacillin or cephalexin for methicillin-susceptible S. aureus (MSSA), or TMP-SMX, doxycycline, or clindamycin if methicillin-resistant S. aureus (MRSA) is suspected. 1

Initial Assessment and Severity Classification

The first step is determining whether the infection is purulent (abscess, furuncle) or nonpurulent (cellulitis without abscess), and assessing severity 1:

• Mild infection: Localized purulent infection without systemic signs 1
• Moderate infection: Purulent infection with systemic signs (fever >38°C, tachycardia >90 bpm, WBC >12,000 or <4,000 cells/µL) 1
• Severe infection: Failed initial treatment, immunocompromised status, or signs of deeper infection 1

Surgical Management

Incision and drainage is the cornerstone of treatment for any purulent finger infection and should be performed under digital anesthesia with extensive lavage. 1, 2

• A study of 103 acute fingertip infections treated with excision and extensive lavage under digital anesthesia showed no recurrences regardless of bacterial type, with mean time to first dressing of 5.7 days 2
• Gram stain and culture should be obtained from purulent material to guide antibiotic therapy 1
• For mild purulent infections with adequate drainage and <5 cm of surrounding erythema, antibiotics may not be necessary if the patient lacks systemic signs 1

Antibiotic Selection

For Methicillin-Susceptible S. aureus (MSSA)

Dicloxacillin or cephalexin for 7 days is the recommended first-line oral therapy for MSSA finger infections. 1, 3

• Dicloxacillin dosing: 250 mg orally every 6 hours for moderate infections; 125 mg every 6 hours for mild infections 4
• Take on an empty stomach (1 hour before or 2 hours after meals) with at least 4 ounces of water 4
• Cephalexin is an equally effective and cost-effective alternative 3
• Continue therapy for at least 48 hours after the patient becomes afebrile and asymptomatic 4

For Methicillin-Resistant S. aureus (MRSA)

When MRSA is suspected or confirmed, use TMP-SMX, doxycycline, or clindamycin for 7 days. 1

• Clindamycin 600 mg orally three times daily is preferred when MRSA is confirmed, particularly in lactating women 5
• TMP-SMX is effective but should be avoided in infants <2 months 1, 5
• Doxycycline is an alternative but should not be used in children <8 years of age 1

For Severe Infections Requiring Hospitalization

Vancomycin or daptomycin is recommended for severe MRSA infections with systemic toxicity. 1, 6

• Vancomycin remains the drug of choice for complicated MRSA infections 5, 7
• Daptomycin 6 mg/kg IV is a noninferior alternative to vancomycin 6
• Once susceptibilities are known, switch MSSA to cefazolin or an antistaphylococcal penicillin 6

Duration of Therapy

A 7-day course of oral antibiotics is adequate for uncomplicated finger infections after adequate drainage. 1, 3

• Although 10-day courses have been used in clinical trials, there is no evidence that this duration is more effective than 7 days 3
• Continue therapy for at least 48 hours after resolution of fever and symptoms 4
• For severe infections with temperature >38.5°C or erythema extending >5 cm, a short course of 24-48 hours of IV antibiotics may be needed before transitioning to oral therapy 1

Important Clinical Considerations

When Antibiotics May Not Be Necessary

In the study of 103 acute fingertip infections treated with complete surgical excision and lavage, antibiotics were not routinely prescribed in the absence of severe comorbidities, with no recurrences observed. 2

• Only 5 of 71 patients (8.2%) without initial antibiotics required delayed prescription at day 5 for wound complications 2
• This suggests that complete surgical drainage may be sufficient for healthy patients with localized infection 2

Culture and Follow-up

Obtain cultures from purulent drainage in all cases requiring antibiotics, particularly if MRSA is suspected or if the patient has failed initial treatment. 1

• S. aureus was the causative organism in 58.3% of finger infections, with polymicrobial flora in 16.5% and Streptococcus in 12.6% 2
• First dressing change should occur at 5-7 days to monitor progression and adjust treatment if necessary 2

Common Pitfalls to Avoid

• Do not use β-lactam antibiotics (penicillins, cephalosporins) for MRSA infections as they are ineffective despite in vitro susceptibility patterns that may appear favorable 7, 8
• Do not prescribe fluoroquinolones or linezolid as monotherapy for staphylococcal infections due to rapid emergence of resistance 1
• Avoid tetracyclines in children <8 years of age and during lactation 1, 5
• Do not delay surgical drainage in favor of antibiotics alone for purulent infections, as drainage is the primary treatment 1, 2