II. Pathophysiology

  1. See Blastomycosis
  2. Caused by Blastomyces dermatidis
  3. Direct contact of non-intact skin with contaminated soil or decomposing timber

III. Symptoms

  1. Painful facial lesions (Pustules, ulcers or wart-type lesions)

IV. Signs

  1. Distribution: Face (esp. eyebrows)
  2. Verrucous form
    1. Starts as Papule or Pustule with slow enlargement
    2. Later, the lesion forms crust with irregular borders
    3. Secondary Subcutaneous Nodules and micro-abscesses may drain pus
  3. Ulcerative form
    1. Ulcerated lesion with sharp border
    2. Friable red granulation tissue at ulcer base may bleed easily

V. Diagnosis

  1. Fungal Culture
  2. Skin biopsy
  3. Microscopy of purulent discharge (with Potassium Hydroxide or Calcofluor stain)
    1. Yeast with broad-based buds (8-15 mm diameter)
  4. Urine Blastomyces Antigen test
    1. False Positive Histoplasma (high cross reactivity between organisms)

VI. Differential Diagnosis

VII. Management

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