What is the best treatment for a fungal infection on the ankle?

Treatment of Fungal Infection on the Ankle

For a fungal infection on the ankle (tinea pedis), topical terbinafine 1% cream applied twice daily for 1 week is the most effective first-line treatment, offering superior cure rates compared to longer courses of azole antifungals. 1

Diagnosis Considerations

Before initiating treatment, confirm the diagnosis:

• Look for characteristic features: scaling, maceration, fissuring, and erythema
• Perform direct microscopy with potassium hydroxide (KOH) preparation to visualize fungal elements
• Consider culture in resistant or atypical cases

Treatment Algorithm

First-Line Treatment

• Topical terbinafine 1% cream:
  • Apply twice daily for 1 week
  • Extend application 2 cm beyond visible lesion borders
  • Continue for at least 1 week after clinical resolution 2
  • Offers superior mycological cure rates (93.5%) compared to clotrimazole (73.1%) 1
  • Fungicidal action provides faster resolution and lower recurrence rates 3

Alternative Treatments

• Topical azoles (if terbinafine is unavailable or not tolerated):
  • Clotrimazole 1% cream: Apply twice daily for 4 weeks 1
  • Miconazole 2% cream: Apply twice daily for 4 weeks 4

For Extensive or Resistant Infections

• Oral antifungal therapy may be required for:

  • Extensive skin involvement
  • Failure of topical therapy after 2-4 weeks
  • Immunocompromised patients 2

• Oral options:

  • Terbinafine 250 mg daily for 2 weeks
  • Itraconazole 200 mg daily for 1-2 weeks
  • Fluconazole 150-300 mg weekly for 2-4 weeks 5

Prevention of Recurrence

• Keep feet clean and dry, especially between toes
• Wear breathable cotton socks and change them daily
• Use flip-flops in public showers, locker rooms, and pool areas 2
• Apply antifungal powder to shoes to eliminate fungal elements 5
• Discard heavily contaminated footwear or treat with antifungal powder 5

Common Pitfalls to Avoid

• Inadequate treatment duration: Continue treatment for at least one week after clinical resolution
• Concurrent steroid use: Avoid combination antifungal/steroid agents unless specifically indicated for inflammation, as they can cause atrophy and mask symptoms 6
• Neglecting fomites: Treat shoes and socks to prevent reinfection 5
• Incomplete family treatment: Consider treating household members if they show signs of infection 2

Special Considerations

• For diabetic patients or those with compromised circulation, monitor closely for secondary bacterial infections
• In cases of concurrent onychomycosis (nail infection), longer treatment courses with oral antifungals may be necessary 5
• For patients with recurrent infections, consider prophylactic use of antifungal powders in shoes 2

Terbinafine's fungicidal mechanism provides faster resolution with shorter treatment duration compared to the fungistatic action of azoles, making it the preferred agent for dermatophyte infections like tinea pedis 3.