Fungal Skin Infections (Dermatophyte Infections, Candidiasis, and Tinea Versicolor)

Basics

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

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