Fungus

Cutaneous Blastomycosis

search

Cutaneous Blastomycosis

  • See Also
  1. Blastomycosis
  • Pathophysiology
  1. See Blastomycosis
  2. Caused by Blastomyces dermatidis
  3. Direct contact of non-intact skin with contaminated soil or decomposing timber
  • Symptoms
  1. Painful facial lesions (Pustules, ulcers or wart-type lesions)
  • 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
  • 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)
  • Differential Diagnosis
  1. Furuncle
  2. Contagious Ecthyma (Orf)
  3. Pyogenic Granuloma
  4. Squamous Cell Carcinoma
  • Management
  1. See Blastomycosis
  • References
  1. Altman (2007) Am Fam Physician 76:1533-4 [PubMed]
  2. Bradsher (2003) Infect Dis Clin North Am 17:21-40 [PubMed]
  3. Gruber (2024) Am Fam Physician 109(5): 467-8 [PubMed]