SHM Converge Scientific Abstract ePoster Gallery-A Wisconsin Rash: Three Cases of Disseminated Blastomycosis

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Blastomycosis is a chronic fungal infection caused by <em>Blastomyces dermatitidis</em>, acquired by inhaling aerosolized conidia. It is most common in the Ohio and Mississippi River valleys, but Wisconsin has especially high incidence rates, particularly in northern counties. Infection may appear as pulmonary disease, disseminated infection, or primary cutaneous disease, making it a major diagnostic mimic.

Immunocompetent patients often develop a self-limited flu-like illness, while older adults and immunocompromised patients are more likely to develop severe pneumonia, respiratory failure, and dissemination. When the disease spreads, the skin is commonly involved first, producing papules and plaques that can resemble cellulitis, followed by lytic bone lesions and other organ involvement. Risk factors include impaired immunity, occupational exposure, and male sex.

The report describes three Wisconsin patients who initially presented with tuberculosis-like symptoms, including cough, hemoptysis, pulmonary nodules, and constitutional complaints, along with cutaneous lesions on the face and extremities. Imaging showed interstitial opacities, multifocal consolidations, cavitary lesions, and granulomatous changes. Despite empiric broad-spectrum antibiotics, they improved little, and repeated AFB cultures and interferon-gamma testing were negative. Diagnosis was ultimately confirmed by skin cultures or tissue biopsy showing broad-based budding yeast and positive urine antigen testing for Blastomyces.

Treatment depends on severity: itraconazole is preferred for moderate disease, while amphotericin B is favored for severe or disseminated infections, especially with CNS involvement. Most patients can be cured with antifungal therapy, but diagnosis is often delayed because blastomycosis can closely mimic tuberculosis and affect virtually any organ system. A high index of suspicion is essential, even in immunocompetent patients.

Asset Subtitle

Harpreet Gill

Meta Tag

Author List Harpreet Gill, Hefei Liu, Komal Khoja, Malek E. Ayoub, Pinky Jha

Category Clinical Vignettes

Concept Blastomycosis

Concept Disseminated Disease

Concept Geographic Distribution

Concept Wisconsin

Concept Clinical Presentation

Distinguished Non-Finalist

Presenter Organization Medical College of Wisconsin

Presenting Author Harpreet Gill

Track Adult

Keywords

blastomycosis

Blastomyces dermatitidis

fungal infection

Wisconsin

pulmonary disease

disseminated infection

cutaneous lesions

broad-based budding yeast

itraconazole

amphotericin B

Blastomycosis

Disseminated Disease

Geographic Distribution

Wisconsin

Clinical Presentation