What is the treatment for a toenail bacterial infection?

Treatment of Toenail Bacterial Infection

For bacterial toenail infections, obtain cultures and initiate oral antibiotics with anti-Staphylococcus aureus and gram-positive coverage, combined with topical antiseptics, while draining any abscess present. 1

Immediate Management Steps

Culture and Diagnosis

• Always obtain bacterial cultures before initiating treatment to identify the causative organism and guide antibiotic selection 1, 2
• The most common bacterial pathogens are Staphylococcus aureus (gram-positive) and Pseudomonas aeruginosa (gram-negative, recognizable by green or black nail discoloration) 2
• Klebsiella species are also possible gram-negative causes 2

Antibiotic Selection by Organism

• For suspected or confirmed Staphylococcus aureus and other gram-positive bacteria: Begin oral antibiotics with anti-staphylococcus coverage 1
• For Pseudomonas aeruginosa infections: Use ciprofloxacin as the treatment of choice 2
• For other bacterial pathogens: Treat according to culture and sensitivity testing results 2

Topical Therapy

• Apply topical antiseptics such as octenidine to the affected nail 2
• Consider topical antibiotics (nadifloxacin or gentamicin) in select cases 2

Surgical Intervention When Indicated

Abscess Drainage

• If a painful subungual abscess or hematoma is present, partial or total nail avulsion is required 1
• The nail bed must be cleaned and cultured at the time of drainage 1
• Severe acute bacterial infections often require surgical drainage to prevent morbidity and disability 3

Important Caveat

• Do not drain suspected herpetic whitlow, as viral infections may mimic bacterial abscesses but require non-operative treatment to prevent sequelae 3
• A more conservative approach is advisable for less severe bacterial infections and chronic nail infections 3

Monitoring and Follow-up

• Reassess after 2 weeks (either by healthcare professional or patient self-report) 1
• If the infection worsens or does not improve after 2 weeks with appropriate antibiotics and drainage, consider treatment failure and reassess the diagnosis 1
• Continue monitoring until the nail plate grows reattached, keeping nails cut regularly during this period 1

Common Pitfalls to Avoid

• Never initiate treatment without obtaining cultures, as incorrect diagnosis is a common cause of treatment failure 1, 2
• Distinguish bacterial from fungal infections: While fungal infections (onychomycosis) are far more common causes of toenail pathology, bacterial infections require completely different treatment approaches 2, 4
• Recognize that trauma or mechanical/chemical injury is usually the trigger enabling bacterial infiltration, and artificial nails or nail polish can harbor microorganisms 3
• Be aware that bacterial infections can represent superinfection complicating other nail or skin disorders 3