Updated: 6/4/2018


Review Topic
  • A 50-year-old man presents with a rash on his right foot. He reports noticing this rash between his fourth and fifth toe a few days ago, and denies any symptoms related to the rash. He has a past medical history of diabetes managed with metformin, and obesity. He lives in Chicago, where it is currently summer and very humid. On physical exam, there is a erythematous and macerated scaly plaque between his fourth and fifth toe. He is given topical antibiotics for management of this disease.
  • Clinical definition
    • superficial infection of the skin caused by Corynebacterium minutissimum
      • characterized by maceration and scaly plaques in skin folds
  • Epidemiology
    • demographics
      • higher in soldiers and hospitalized patients
      • rare in children
    • risk factors
      • humid conditions
      • immunocompromised state
      • diabetes
      • obesity
      • hyperhidrosis
  • Etiology
    • infection by gram-positive bacillus, C. minutissimum
  • Pathogenesis
    • C. minutissimum is a part of normal skin flora
    • if conditions are too moist or occlusive, the bacteria can proliferate in the stratum corneum, disrupting the skin and causing maceration and flaky plaques
  • Associated conditions
    • trichomycosis axillaris
      • another condition caused by C. tenuis
  • Symptoms
    • may be asymptomatic or pruritic
  • Physical exam
    • location
      • toe webs (most common)
        • scaling
        • maceration of toe web spaces
      • intertriginous (groin or axilla most common)
        • erythematous thin plaques
        • initially red but can progress to brown
        • lesions have overlying fine scaling and wrinkling
        • “cigarette paper”-like
  • Wood’s lamp examination
    • coral-red fluorescence
  • Gram stain of skin scraping
    • gram-positive filaments and rods
  • KOH preparation
    • to rule out simultaneous dermatophyte infection
  • Diagnostic criteria
    • typically based on clinical exam and history
    • Wood’s lamp exam can confirm diagnosis
  • Seborrheic dermatitis
    • negative Wood’s lamp examination
    • greasy scaling
  • Tinea versicolor
    • negative Wood’s lamp examination
  • Medical
    • topical therapy
      • indication
        • localized disease
      • drugs
        • clindamycin/erythromycin
        • fusidic acid
        • imidazole antifungals
          • has activity against some gram-positive bacteria, including C. minutissimum
    • oral therapy
      • indications
        • widespread disease
      • drugs
        • erythromycin
        • clarithromycin
  • Secondary bacterial infection

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