Treatment of Bacterial Toenail Infection
For true bacterial toenail infections, topical antiseptics like octenidine are first-line, with oral ciprofloxacin specifically indicated for Pseudomonas infections (recognizable by green or black nail discoloration), while other bacterial pathogens should be treated according to culture and sensitivity results. 1
Critical First Step: Confirm the Diagnosis
- Obtain mycological confirmation before assuming fungal infection - most "toenail infections" are actually fungal (onychomycosis), not bacterial 2
- Bacterial nail infections are far less common than fungal infections and typically caused by gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella spp.) or gram-positive bacteria (Staphylococcus aureus) 1
- Green or black nail discoloration strongly suggests Pseudomonas aeruginosa infection 1
- Culture and sensitivity testing should guide antibiotic selection for non-Pseudomonas bacterial infections 1
Treatment Algorithm for Bacterial Infections
For Pseudomonas Infections:
- Oral ciprofloxacin is the treatment of choice 1
- Topical antiseptics (octenidine) can be used as adjunctive therapy 1
For Other Bacterial Infections:
- Topical antiseptics (octenidine) are first-line for most bacterial nail infections 1
- Topical antibiotics (nadifloxacin, gentamicin) may be used in select cases 1
- Systemic antibiotics should be guided by culture and sensitivity results 1
- Surgical drainage is required if abscess formation is present 3
Important Clinical Pitfalls
- Do not confuse herpetic whitlow (viral) with bacterial abscess - herpetic whitlow mimics abscess but requires non-operative treatment, while bacterial abscess requires drainage 3
- Most nail unit infections presenting to clinicians are actually fungal (dermatophyte infections), not bacterial 2, 1
- Artificial nails and nail polish can harbor bacteria and predispose to infection 3
- Trauma (mechanical or chemical) is usually the trigger enabling bacterial infiltration 3
When Fungal Infection is Actually Present
If mycological testing confirms fungal rather than bacterial infection:
- Terbinafine 250 mg daily for 12-16 weeks is first-line for dermatophyte toenail infections, with cure rates of 70-80% 2, 4
- Itraconazole 400 mg daily for 1 week per month (3-4 pulses) is second-line for dermatophytes and first-line for Candida infections 2, 4
- Treatment should not be commenced before mycological confirmation 2