Treatment of Ingrown Toenail with Keflex (Cephalexin)
Keflex (cephalexin) should only be used for ingrown toenails when there is clear evidence of bacterial infection with cellulitis, purulent drainage, or significant erythema—otherwise, initial management should focus on conservative measures with topical antiseptics and anti-inflammatory agents. 1, 2
When Antibiotics Are NOT Needed
The majority of ingrown toenails do not require systemic antibiotics initially. Start with conservative management using topical povidone iodine 2% twice daily as the primary antiseptic agent, combined with a mid- to high-potency topical corticosteroid ointment applied to the nail fold twice daily. 1, 2
- Conservative approaches include warm soaks, proper nail trimming (straight across, never rounded), and ensuring well-fitting footwear with adequate toe room 1, 3, 4
- Cotton wisps or dental floss placement under the ingrown nail edge, or gutter splinting, can provide immediate relief 3, 4, 5
- Daily dilute vinegar soaks (50:50 dilution) for 10-15 minutes twice daily serve as useful adjunctive measures 2
When to Use Antibiotics (Including Keflex)
Add oral antibiotics only when localized cellulitis, purulent drainage, or significant erythema develops despite conservative measures. 1
Preferred Antibiotic Choice
- Amoxicillin-clavulanate (Augmentin) is the recommended first-line oral antibiotic for ingrown toenails requiring systemic therapy, as it provides coverage for Staphylococcus aureus and gram-positive organisms 1, 6
- Adult dosing: 500 mg/125 mg every 12 hours 6
- Pediatric dosing: weight-based dosing per American Academy of Pediatrics guidelines 1
Why Keflex Is Not First-Line
While Keflex (cephalexin) provides gram-positive coverage, amoxicillin-clavulanate is specifically recommended in current guidelines because secondary infections in ingrown toenails involve both gram-positive and gram-negative organisms in up to 25% of cases. 2 The broader coverage of Augmentin makes it superior to Keflex for this indication.
Critical Clinical Pitfalls
- Avoid topical corticosteroids if purulent drainage is present until the infection is adequately treated with antibiotics 2
- Consider bacterial cultures before starting antibiotics in severe cases or treatment failures 6
- Reassess after 2 weeks; if no improvement with conservative measures, escalate to antibiotics or consider surgical intervention 2
- Secondary fungal infections occur in up to 25% of paronychia cases and may require antifungal therapy if not responding to antibiotics 6
Surgical Considerations
Surgical approaches (partial nail avulsion with phenolization or matricectomy) are superior to nonsurgical treatment for preventing recurrence and should be considered for moderate to severe cases or recurrent ingrown toenails. 3, 4, 7
- Partial nail avulsion combined with phenolization is more effective at preventing symptomatic recurrence compared to surgical excision without phenolization, though it carries a slightly increased risk of postoperative infection 3
- Oral antibiotics before or after phenolization do not improve outcomes 3