What are the presentation and treatment of Tinea pedis (athlete's foot)?

Tinea Pedis Presentation and Treatment

Tinea pedis (athlete's foot) is most effectively treated with terbinafine 1% cream applied twice daily for 1-2 weeks, which achieves mycological cure rates of up to 93.5% after just one week of treatment. 1, 2

Clinical Presentation

Tinea pedis presents in three main clinical forms:

1. Interdigital type - Most common presentation

   • Maceration and scaling between toes (especially 4th and 5th web spaces)
   • Pruritus, burning sensation
   • Fissuring of skin

2. Hyperkeratotic (moccasin-type)

   • Diffuse scaling and hyperkeratosis of soles, heels, and sides of feet
   • Chronic presentation with dry, scaly appearance
   • May extend to dorsal surface

3. Vesiculobullous (inflammatory)

   • Vesicles or bullae formation, usually on instep or anterior plantar surface
   • More acute presentation with significant inflammation
   • Can be accompanied by secondary bacterial infection

The accuracy of clinical diagnosis alone is low, so confirmation with KOH wet-mount examination of skin scrapings from active lesion borders is recommended 3.

Epidemiology and Risk Factors

• Affects approximately 3% of the world population
• More common in males than females
• Peak incidence between ages 16-45
• Higher prevalence in athletes, diabetics, and immunocompromised individuals
• Most commonly caused by Trichophyton rubrum and Trichophyton interdigitale 3, 1

Treatment Algorithm

1. Topical Treatment (First-Line for Uncomplicated Cases)

Preferred Agent:

• Terbinafine 1% cream - Apply twice daily 1, 2
  • For interdigital infection: 1 week treatment
  • For plantar/moccasin type: 2 weeks treatment

Alternative Topical Agents:

• Ciclopirox olamine 0.77% cream/gel - Apply twice daily for 4 weeks (60% cure at end of treatment, 85% cure two weeks post-treatment) 1
• Azoles (miconazole, clotrimazole) - Apply twice daily for 2-4 weeks 1

2. Oral Treatment (For Severe/Extensive Disease or Treatment Failures)

Indications for oral therapy:

• Extensive involvement
• Failure of topical therapy
• Concomitant onychomycosis
• Immunocompromised patients

Preferred Oral Agents:

• Terbinafine 250 mg once daily for 1-2 weeks 1
• Itraconazole 100 mg daily for 2 weeks 1
• Fluconazole (alternative if unable to tolerate others) 4, 1

Prevention and Management of Recurrence

1. Footwear management:

   • Wear well-fitting, ventilated shoes
   • Change shoes and socks at least once daily
   • Apply antifungal powders containing miconazole, clotrimazole, or tolnaftate to shoes 1, 2
   • For heavily contaminated footwear: discard or decontaminate with naphthalene mothballs in sealed plastic bag for 3 days 4, 1

2. Foot hygiene:

   • Thoroughly dry between toes after bathing
   • Wear cotton, absorbent socks and change daily
   • Apply foot powder after bathing (reduces infection rates from 8.5% to 2.1%) 1

3. Family treatment:

   • Treat all infected family members simultaneously to prevent reinfection 4

Treatment Pitfalls and Considerations

1. Common reasons for treatment failure:

   • Inadequate treatment duration
   • Neglecting environmental factors (contaminated footwear)
   • Missing concomitant infections (tinea cruris)
   • Not treating infected family members 1

2. Special populations:

   • Athletes: Higher prevalence due to trauma, sweating, and exposure to infectious environments. Preventive measures are crucial 4
   • Diabetics: Almost three times more likely to develop infection with higher risk of complications. Regular foot checks are essential 4
   • Children under 12: Consult a doctor before using topical terbinafine 2

3. Monitoring:

   • For oral terbinafine: monitor for rare hepatotoxicity or neutropenia 1
   • For persistent or worsening symptoms: reevaluate diagnosis and consider bacterial superinfection

The evidence strongly supports terbinafine as the most effective treatment for tinea pedis, with studies showing it achieves superior cure rates with shorter treatment duration compared to other antifungals. One study demonstrated terbinafine 1% cream applied twice daily for 1 week was significantly superior to a 4-week course of clotrimazole 1% cream 5.