Description

• Superficial fungal infection of the skin of the feet caused by dermatophytes
• Most common dermatophyte infection encountered in clinical practice; contagious
• Often accompanied by tinea manuum, tinea unguium, and tinea cruris
• Clinical forms: interdigital (most common), hyperkeratotic (moccasin type), vesiculobullous (inflammatory), and rarely ulcerative
• System(s) affected: skin/exocrine
• Synonym(s): athlete’s foot, foot ringworm

Epidemiology

• Predominant age: 20 to 50 years, although can occur at any age
• Predominant gender: males infected about 4 times as frequently as females

Prevalence

• 4–10% of the population
• >70% of population will experience during a lifetime.

Pediatric Considerations
Rare in younger children; common in adolescents

Geriatric Considerations
Elderly are more susceptible to outbreaks because of immunocompromised and impaired perfusion of distal extremities.

Etiology and Pathophysiology

Superficial infection caused by dermatophytes that release enzymes called keratinases to invade and thrive only in nonviable keratinized tissue

• Trichophyton interdigitale (acute)
• Trichophyton rubrum (chronic): most common
• Trichophyton tonsurans
• Epidermophyton floccosum

Genetics
No known genetic pattern

Risk Factors

• Hot, humid weather
• Sweating
• Occlusive/tight-fitting footwear
• Immunosuppression
• Prolonged application of topical steroids

General Prevention

• Good personal hygiene
• Wearing rubber or wooden sandals in community showers, bathing places, locker rooms
• Careful drying between toes after showering or bathing; blow-drying feet with hair dryer may be more effective than drying with towel
• Changing socks and shoes frequently
• Applying drying or dusting powder
• Applying topical antiperspirants

Commonly Associated Conditions

• Hyperhidrosis
• Onychomycosis
• Tinea manuum/unguium/cruris/corporis