Description

Superficial fungal infections of the skin, hair, and nails are characterized by erythema, scaling, pruritus, and change in coloration.

Epidemiology

• Dermatophyte infections:
  • Tinea capitis:
    • Most common fungal infection in pediatric population
    • Occurs mainly in prepubescent children (between ages 3 and 7 years)
    • Asymptomatic carriers are common and contribute to spread.
  • Tinea corporis usually seen in younger children or in young adolescents with close physical contact to others (i.e., wrestlers).
  • Onychomycosis: Overall prevalence is 0–2.6% in children, often occurs with concomitant tinea pedis, or in 1st-degree relatives with infection.
• Candidiasis: majority of infants colonized with Candida albicans
• Tinea versicolor: seen in adolescents and young adults

General Prevention

• Measures should be taken to avoid transmission between hosts, including no sharing of combs, brushes, hats, etc.
• Hair utensils and hats should be washed in hot, soapy water at onset of therapy.
• Pets should be watched and treated early for any suspicious lesions.
• In patients in whom appropriate therapy has not led to improvement in symptoms, siblings and close contacts should be examined and fungal cultures performed.
• Isolation of hospitalized patient is unnecessary.

Pathophysiology

• Fungal elements (arthroconidia) adhere to stratum corneum or hair shaft. Proteases work to degrade keratin, which allows for invasion of dermatophytes.
• Predisposing factors may include moisture, macerated skin, and immunocompromised.
• Host immune response is usually able to contain infection.
• Inflammatory response is variable; highly inflammatory forms may lead to pustular lesions and kerion (large inflammatory mass) formation.

Etiology

• Varies by geographic region
• Dermatophyte infections:
  • Tinea capitis: >90% caused by Trichophyton tonsurans in North America—spread from human to human (anthropophilic); increasing incidence of Microsporum canis infection spread from animals such as cats and dogs to humans (zoophilic)
  • Tinea corporis: preadolescent children: M. canis, Microsporum audouinii; older children: Trichophyton rubrum, Trichophyton mentagrophytes, T. tonsurans
  • Onychomycosis: T. rubrum, T. mentagrophytes
• Candidiasis: usually C. albicans
• Tinea versicolor: Malassezia furfur