Blastomycosis Differential Diagnoses

Updated: Jan 09, 2019
  • Author: Chidinma Chima-Melton, MD; Chief Editor: Zab Mosenifar, MD, FACP, FCCP  more...
  • Print

Diagnostic Considerations

Blastomycosis should be considered in the differential diagnosis of an atypical pulmonary infection in regions where it is endemic, even in urban areas.

Blastomycosis may present as a community-acquired pneumonia; in addition, it should be considered in any patient with pneumonia that is not resolving, or one who presents with acute respiratory distress syndrome (ARDS). Establishing blastomycosis as the cause of pneumonia is often difficult, and most patients received multiple antibiotic courses before being diagnosed. Delays in diagnosis of pulmonary blastomycosis can be reduced if a higher clinical suspicion exists and there is earlier use of sputum potassium hydroxide (KOH) fungal smear, especially after a course of antibiotics has failed to result in clinical improvement. [43]

Other pulmonary disorders to consider in the differential diagnosis are sarcoidosistuberculosis, and other endemic mycoses such as histoplasmosis and coccidioidomycosis.

Blastomycosis has a tendency to mimic carcinoma. Pulmonary blastomycosis may resemble lung cancer, and blastomycosis osteomyelitis may resemble bony metastasis. Central nervous system blastomycosis may resemble brain neoplasm. The typical verrucous or ulcerative cutaneous lesions of blastomycosis may mimic skin cancers, such as basal cell carcinoma and squamous cell carcinoma. Other skin disorders to consider include the following:

Differential Diagnoses