Tinea Pedis

Tinea pedis, commonly known as athlete’s foot, is a fungal infection of the foot caused by dermatophytes.

• Prevalence: It is the most prevalent fungal infection of the skin, especially common in warm, moist environments.

Causes

• Pathogens:
  • Trichophyton rubrum
  • T. interdigitale (previously T. mentagrophytes var. interdigitale)
  • Epidermophyton floccosum

Risk Factors

• Direct contact: Transmission through direct contact with infected surfaces or skin scales.
• Environmental: Exposure in communal areas like showers, locker rooms, and swimming pools.
• Personal habits: Sharing towels, shoes, or socks with an infected person.
• Occlusive footwear: Wearing tight, non-breathable footwear.
• Excessive sweating: Individuals with hyperhidrosis are at higher risk.
• Immune system: Those with weakened immune systems or on immunosuppressive medications.
• Diabetes: Increases susceptibility due to impaired immune response and circulation.
• Poor hygiene: Inadequate drying of feet, particularly between toes.

Clinical Features

• Interdigital: Itching, scaling, and fissuring between toes; most common between the 4th and 5th toes.
• Moccasin type: Thickening and scaling of the heels and soles.
• Vesiculobullous type: Blisters containing clear fluid, typically on the inner aspects of the foot.
• Ulcerative type: Less common, presenting with oozing and painful ulcerations.

Diagnosis

• Clinical examination: Inspecting foot, toenails, and other body sites for fungal infection.
• Microscopy and culture: Skin scrapings treated with potassium hydroxide to reveal fungi or cultured to identify specific organism.

Differential Diagnoses

• Dermatitis: Both irritant and allergic, presenting with similar symptoms but without fungal elements.
• Psoriasis: May mimic hyperkeratotic tinea but usually has a symmetrical pattern.
• Pustular disorders: Such as plantar pustulosis, often misdiagnosed as fungal infections.

Treatment

Non-Pharmacological

• Hygiene: Thoroughly drying feet, especially between toes, after washing.
• Footwear: Wearing well-ventilated shoes and changing them regularly.
• Environmental control: Cleaning floors with antifungal or bleach solutions in communal areas.
• Barrier protection: Using sandals in public showers or locker rooms.

Pharmacological

Topical Antifungals

• Types: Azoles (e.g., clotrimazole), allylamines (e.g., terbinafine), butenafine, ciclopirox, and tolnaftate.
• Application: Applied once or twice daily, usually for 2 to 4 weeks, depending on the severity and location of the infection.

Oral Antifungals

• Indications: Used when topical treatment is ineffective or for extensive, moccasin-type infections.
• Options: Terbinafine, itraconazole, fluconazole, and griseofulvin (less commonly due to lesser efficacy).
• Duration: Usually a few weeks, based on clinical response and mycological clearance.

Prevention

• Personal care: Regular use of antifungal powders or sprays, especially in those with recurrent episodes.
• Foot care: Maintaining dry feet and using breathable footwear.
• Environmental measures: Treating shoes with antifungal powders and ensuring cleanliness of communal wet areas.