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Tinea (Dermatophytes)

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Summary

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Key Points

  • Tinea
    • Characteristics
      • Fungal cutaneous (skin) infections
      • Dermatophytes implicated
        • Microsporum
          • Animal contact associated with Microsporum
        • Trichophyton
        • Epidermophyton
    • Presentation
      • Presents with ring-like (annular) scaling plaques
        • Well-demarcated, raised erythematous borders, with central clearing
      • Associated with pruritus (itchiness)
      • Diseases named for part of the body they affect
      • Tinea capitis = head/scalp
        • Pruritic lesions on scalp
        • Most common in pre-pubertal boys
        • Acquired through direct contact with fungus
      • Tinea corporis = body
        • Occurs on body (usually torso)
        • Can be acquired from contact with infected pets or farm animals
          • Classically in athletes with skin-to-skin contact (wrestlers) (mb)
      • Tinea cruris = groin
        • Also known as “jock itch”; occurs in inguinal area
      • Tinea pedis = foot
        • Also known as “athlete’s foot”
        • Seen with occlusive footwear or barefoot walkers
      • Tinea unguium = nails
        • Type of onychomycosis (fungal nail infection)
        • Thickened nails with white, yellow, or brown discoloration
    • Diagnosis
      • Branching septate hyphae visible on KOH preparation with blue fungal stain
      • Wood’s lamp exam reveals green fluorescence of infected hairs
    • Treatment
      • Topical or oral antifungals used, depending on severity
      • Azoles (fluconazole)
      • Terbinafine
        • Inhibits squalene epoxidase, which inhibits synthesis of ergosterol needed for fungal membrane
      • Griseofulvin
        • Inhibits fungal mitosis and binds to keratin
      • Operative treatment may be required for deep nail infections