Updated: 12/16/2021

Tinea Corporis

Review Topic
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  • Snapshot
    • A 10-year-old boy presents witha worsening rash on his forearms and flank. His mother reports that there are several red circular areas that have grown in size, becoming shaped like rings. The family recently got a new puppy, which has been sleeping in the boy's bed. On physical exam, the circular lesions are scaly with sharply marginated plaques. They are annular in configuration with concentric rings, and central clearing. Scrapings of the lesions are tested, and a topical medication is prescribed.
  • Introduction
    • Clinical definition
      • superficial fungal infection of the skin
      • "corporis" = "body"
        • affected areas include the trunk, legs, arms, and neck
        • does not include the feet, hands, groin, nails, and scalp
          • these tinea infections are classified differently
  • Epidemiology
    • Demographics
      • most common in pre-adolescents
      • classically in athletes with skin-to-skin contact (wrestlers)
    • Risk factors
      • exposure to an infected person or animal
      • may be acquired from tinea capitis
        • this is the most common cause in children
      • immunocompromised state
  • Etiology
    • Pathogenesis
      • infection of the epidermis
        • occasionally spreads to the hair follicles
    • Dermatophyte fungal infection
      • most commonly from the
        • trychophyton and microsporum genera
          • trychophyton rubrum is the most common
    • Caused by direct contact with the fungus
      • infection on another person or animal
        • especially kittens and puppies
      • infection from another location
        • e.g. tinea cruris, tinea pedis, etc.
  • Presentation
    • Symptoms
      • single or multiple pruritic areas of rash
      • may be asymptomatic
    • Physical exam
      • begins as an erythematous, scaly patch or plaque in a circular or oval shape
      • spreads outward, with central clearing
      • sharply marginated
        • with a raised border that advances
      • multiple lesions may coalesce
      • may become extensive
        • should raise suspicion for immune compromise
      • may be inflammatory with significant erythema
        • more common in infection from animals
  • Studies
    • Labs
      • potassium hydroxide (KOH) prep
        • commonly done to confirm diagnosis
        • performed on scrapings from lesions
        • will show characteristic segmented hyphae of dermatophytes
    • Culture
      • may be used for definitive diagnosis
      • much slower than KOH prep
  • Differential
    • Subacute cutaneous lupus erythematosus
      • will be erythematous, ring-shaped, scaly plaques on sun-exposed skin
    • Granuloma annulare
      • benign inflammatory condition
      • will have multiple erythematous plaques on the extremities
      • does not exhibit scaling
    • Pitariasis rosea
      • will show circular, erythematous lesions and may exhibit scaling
      • scale will appear as "collarette"
      • may show "christmas tree-like" distribution on back, following lines of tension
  • Treatment
    • Medical
      • topical antifungal
        • medications
          • azoles
          • terbinafine
          • naftifine
          • note, topical nystatin is not effective against dermatophytes
      • systemic antifungal therapy
        • indication
          • extensive skin involvement
          • failure of topical therapy
        • medications
          • itraconazole
          • terbinafine
          • griseofulvin and fluconazole are second line systemic therapies
  • Prognosis
    • Excellent
      • most cases resolve with treatment
  • Complications
    • Infection may be extensive in the setting of underlying immunodeficiency
      • e.g. HIV/AIDS, diabetes
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(M2.DM.13.2) A 16-year-old Caucasian boy presents to your family practice office complaining of itchiness. He denies other symptoms. He also denies tobacco, alcohol, or other illicit drug use and is not sexually active. He has no other significant past medical or surgical history aside from a meniscal repair from a wrestling injury sustained two years ago from which he has recovered fully. Vitals are T 98.3, HR 67, BP 110/70. On exam you note several pruritic, erythematous, slightly raised annular patches with central clearing on his back.

Which of the following additional tests or features are sufficient to make the diagnosis of this boy's skin lesion?

QID: 104213

Acid-fast bacilli on smear from skin scrapings



History of recent herald patch and lesions along skin cleavage lines



Presence of hyphae when KOH added to skin scrapings



Symmetrical distribution on bilaterial extremities progressing proximally



History of time spent in a Lyme-endemic region



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