Treatment of Non-Fungal (Bacterial) Fingernail Infection
For bacterial fingernail infections, initiate warm water soaks with or without antiseptic solutions as first-line therapy, escalating to topical antibiotics (with or without topical steroids) if inflammation persists, and reserve oral antibiotics only for severe infections or when adequate drainage of an abscess cannot be achieved. 1
Initial Assessment and Classification
Determine if the infection is acute or chronic:
- Acute bacterial paronychia presents with rapid onset (hours to days) of pain, erythema, and swelling of the nail fold, often with visible purulent material 1
- Chronic paronychia persists for ≥6 weeks and represents an irritant dermatitis with secondary bacterial colonization, characterized by absent cuticle and mild nail dystrophy 1, 2
Identify the causative organism based on clinical presentation:
- Green or black nail discoloration indicates Pseudomonas aeruginosa infection 3
- Purulent drainage with erythema suggests Staphylococcus aureus or polymicrobial infection 1
- Klebsiella species and other gram-negative bacteria are also possible 3
Treatment Algorithm for Acute Bacterial Paronychia
Step 1: Conservative Management (First-Line)
Begin with warm water soaks:
- Apply warm soaks 3-4 times daily 1
- Add Burow solution (aluminum acetate) or 1% acetic acid to enhance antimicrobial effect 1
- Continue for 48-72 hours to assess response 1
Step 2: Topical Therapy (If Soaks Fail)
Apply topical antibiotics when simple soaks do not relieve inflammation:
- Use topical antiseptic agents such as octenidine 3
- Consider topical antibiotics like nadifloxacin or gentamicin 3
- Topical antibiotics may be combined with topical steroids to reduce inflammation 1
Step 3: Abscess Drainage (If Present)
Determine if an abscess is present, which mandates immediate drainage:
- Drainage options range from instrumentation with a hypodermic needle to wide incision with a scalpel 1
- Adequate drainage is the definitive treatment for abscess formation 1
Step 4: Oral Antibiotics (Reserved for Specific Situations)
Oral antibiotics are usually not needed if adequate drainage is achieved, unless:
- The patient is immunocompromised 1
- A severe infection is present with systemic signs 1
- Adequate drainage cannot be achieved 1
When oral antibiotics are indicated:
- For Pseudomonas infections: Use ciprofloxacin 3
- For other bacteria: Base therapy on the most likely pathogens and local resistance patterns 1
- Amoxicillin-clavulanate or clindamycin are reasonable empiric choices for polymicrobial infections 4, 5
Treatment Algorithm for Chronic Bacterial Paronychia
Chronic paronychia requires a fundamentally different approach than acute infection:
Primary Strategy: Eliminate Irritants
- Identify and stop exposure to chemical irritants (acids, alkalis, water) commonly encountered by housekeepers, dishwashers, bartenders, florists, bakers, and swimmers 1
- Avoid artificial nails and nail polish, which harbor microorganisms 6
Anti-Inflammatory Therapy
- Apply topical steroids or calcineurin inhibitors to treat the underlying inflammation 1
- Treatment may take weeks to months 1
Adjunctive Antimicrobial Therapy
- Consider topical antiseptics for secondary bacterial colonization 3
- Oral antibiotics are rarely indicated unless acute superinfection occurs 2
Critical Pitfalls to Avoid
Do not confuse viral infections with bacterial abscesses:
- Herpetic whitlow may mimic a bacterial abscess but requires non-operative treatment 6
- Surgical drainage of herpetic whitlow can cause severe sequelae 6
Do not prescribe oral antibiotics as first-line therapy:
- Most acute bacterial paronychia responds to conservative measures alone 1
- Oral antibiotics without drainage of an abscess will fail 1
Do not treat chronic paronychia with antibiotics alone:
- The underlying problem is irritant dermatitis, not active infection 1, 2
- Antifungals are often prescribed unnecessarily when Candida is cultured, but this usually represents colonization rather than primary infection 2
Patient Education for Prevention
Instruct patients to: