Dermatophytosis

    Article Contributors: 
    Sean Klepper M.D.
    Artur Zembowicz M.D....

    Clinical Features:

    • Common cutaneous or ungual infection caused by members of three genera of fungi: Epidermophyton, Microsporum and Trichophyton.
    • Clinically named according to the site of infection:
      • Tinea capitis: Infection of the scalp.  Varies from mild erythema to inflammatory lesions with pustules and folliculitis
      • Tinea corporis: Infection of glaborous skin.  Also known as "ringworm."  Presents as an erythematous, centrifugally growing annular lesion with a peripheral scale.
      • Tinea barbae: Infection of the beard area
      • Tinea cruris: Infection of the inguinal area.  Also known as "jock itch."  Almost exclusively seen in males.
      • Tinea pedis: Infection of the foot.  Also known as "athlete's foot."  There are three types: plantar moccasin-like, interdigital and vesiculobullous.
      • Tinea manuum: Infection of the hand.  Often coexists with tinea pedis.  Most often presents as hyperkeratosis with prominent flexural creases.
      • Tinea unguium: Infection of the nails.  Also known as onychomycosis. 

    Histologic Features:

    • The histologic findings are highly variable.
    • Epidermal changes may include:
      • Neutrophilic infiltrate
      • Compact orthokeratosis
      • "Sandwich sign": hyphae "sandwiched" between an upper normal-appearing stratum corneum and a lower layer of compact orthokeratosis or parakeratosis
      • Mild spongiosis (Significant spongiosis and vesiculation may be present on acral skin.)
      • Acanthosis in chronic lesions
    • Dermal changes may include:
      • Mild superficial edema
      • A mild to moderate perivascular infiltrate of lymphocytes and occasional neutrophils and eosinophils
    • Fungal forms in the form of yeasts and bizarre hyphae are best appreciated on PAS or GMS stains. 
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  • Dermatophytosis
    Author: Artur Zembowicz M.D. Ph.D.

    Conference: DermatopathologyConsultations.com Teaching Collection