Chapter 125: Tinea Pedis

Patient Story

An 8-year-old boy presents with itching between his toes for 1 month (Figure 125-1). The pediatrician looks between his toes and sees maceration with white material. The patient was diagnosed with tinea pedis and treated successfully with a topical nonprescription antifungal medication.

Introduction

Tinea pedis is a common cutaneous infection of the feet caused by dermatophyte fungus. The clinical manifestation presents in 1 of 3 major patterns: interdigital, moccasin, and inflammatory. Concurrent fungal infection of the nails (onychomycosis) occurs frequently.

Synonyms

Athlete’s foot.

Epidemiology

• Tinea pedis is thought to be the world’s most common dermatophytosis.¹

• 70 percent of the population will be infected with tinea pedis at some time.¹

• More commonly affects males than females.¹

• Prevalence increases with age and it is rare before adolescence.¹

Etiology and Pathophysiology

• A cutaneous fungal infection most commonly caused by Trichophyton rubrum.¹

• Trichophyton mentagrophytes and Epidermophyton floccosum follow in that order.

• T. rubrum causes most tinea pedis and onychomycosis.

Risk Factors

• Male gender.

• Use of public showers, baths, or pools.²

• Household member with tinea pedis infection.²

• Certain occupations (miners, farmers, soldiers, meat factory workers, or marathon runners).²

• Use of immunosuppressive drugs.

Diagnosis

Typical Distribution and Morphology

Three types of tinea pedis:

• Interdigital type—Most common (Figure 125-2).

• Moccasin type (Figure 125-3).

• Inflammatory/vesicular type—Least common (Figure 125-4).

Some authors describe an ulcerative type (Figure 125-5).