Is Keflex (Cephalexin) Effective for Treating an Ingrown Toenail?
Yes, Keflex (cephalexin) is the recommended first-line antibiotic for infected ingrown toenails, providing appropriate coverage against Staphylococcus aureus, the primary pathogen in these infections. 1
When Antibiotics Are Actually Indicated
Before prescribing Keflex, you must confirm true bacterial infection is present. Antibiotics are only indicated when you observe purulent drainage, significant erythema extending beyond the nail fold (cellulitis), or abscess formation. 1 Many ingrown toenails are purely inflammatory without bacterial superinfection and do not require antibiotics at all.
- Simple inflammation without purulent drainage should be managed with antiseptic soaks and topical corticosteroids, not antibiotics 1, 2
- The presence of pus or abscess formation definitively indicates bacterial infection requiring antibiotic coverage 1
Antibiotic Selection Algorithm
First-line choice: Cephalexin (Keflex) is recommended by the American College of Physicians as initial therapy for infected ingrown toenails 1
Second-line if treatment fails: Switch to sulfamethoxazole-trimethoprim (Bactrim) if initial cephalexin therapy fails or if MRSA coverage is specifically needed 1
Alternative option: Augmentin (amoxicillin-clavulanate) 500 mg/125 mg every 12 hours can be used for mild to moderate paronychia that accompanies ingrown toenails 1
Critical Clinical Pitfalls to Avoid
Up to 25% of ingrown toenail cases develop secondary bacterial or fungal superinfections. 1, 3 If your patient is not responding to cephalexin after 2 weeks, you must:
- Obtain bacterial cultures to guide antibiotic selection, especially in severe cases or treatment failures 1
- Consider fungal cultures and potential antifungal treatment, as fungal superinfection may be the culprit 1
- Reassess whether surgical intervention is needed rather than continued antibiotic therapy 3
Essential Adjunctive Measures Beyond Antibiotics
Antibiotics alone are insufficient. You must combine cephalexin with warm antiseptic soaks using dilute vinegar (50:50 dilution) or 2% povidone-iodine for 10-15 minutes twice daily. 1, 2 This combination approach addresses both infection and the mechanical foreign body reaction.
Additional measures include:
- Apply mid- to high-potency topical corticosteroid ointment to the nail fold twice daily to reduce inflammation 2
- Place cotton wisps or dental floss under the ingrown nail edge to separate it from the lateral fold 4
- Consider gutter splinting for immediate pain relief 4
Special Population: Diabetic Patients
Diabetic patients with ingrown toenails require immediate treatment by a trained healthcare professional due to high risk of progression to foot ulceration with significant morbidity. 1, 2 The International Working Group on the Diabetic Foot emphasizes this cannot be managed casually, as these patients are at substantially higher risk for complications including limb-threatening infections.
When Surgical Intervention Supersedes Antibiotics
If infection is severe (grade 3 paronychia) with extensive cellulitis or abscess formation, oral antibiotics should be combined with surgical drainage or partial nail avulsion rather than relying on antibiotics alone. 3 Surgical approaches are superior to nonsurgical ones for preventing recurrence in moderate to severe cases 4