Can coccidiomycosis cause granulomas?

Coccidioidomycosis Does Cause Granulomas

Yes, coccidioidomycosis definitively causes granulomas as part of its pathophysiology, particularly in pulmonary nodules and disseminated disease. 1 This granuloma formation represents the host's immune response to contain the fungal infection.

Pathophysiology of Coccidioidal Granulomas

Coccidioidomycosis infection typically follows this progression:

1. Initial infection: Inhalation of arthroconidia (airborne spores) from endemic soil
2. Transformation: Arthroconidia transform into spherules in the lungs
3. Immune response: Host forms granulomas around the fungal elements
4. Granuloma characteristics:
   • Contain actively rupturing spherules 1
   • Create focal areas of tissue destruction
   • Represent the body's attempt to wall off and contain the infection 2

Clinical Manifestations of Granulomatous Disease

Pulmonary Nodules

• Solitary pulmonary nodules due to coccidioidomycosis are granulomatous in nature 1
• These nodules can mimic malignancy on imaging studies
• PET scans often show increased metabolic activity in coccidioidal granulomas, making them difficult to distinguish from malignant lesions 1

Extrapulmonary Manifestations

Granulomatous lesions can occur in various extrapulmonary sites:

• Skin and soft tissue: Granulomatous lesions in 15-67% of patients with disseminated disease 3
• Bone and joints: Osteomyelitis with granuloma formation
• Meninges: Granulomatous meningitis
• Lymph nodes: Common site of granulomatous infection 3

Diagnostic Considerations

When evaluating a patient with suspected coccidioidal granulomas:

• Imaging: Pulmonary nodules on chest X-ray or CT scan
• Serology: May be positive but cannot definitively prove a nodule is coccidioidal 1
• Histopathology: Biopsy showing granulomatous inflammation with spherules is diagnostic
• Skin testing: Can confirm prior infection but cannot prove etiology of a specific lesion 1

Management Implications

The granulomatous nature of coccidioidomycosis impacts treatment decisions:

• Asymptomatic pulmonary nodules: Once confirmed as coccidioidal granulomas, no antifungal treatment is recommended 1
• Symptomatic or progressive granulomas: Oral azole therapy (fluconazole or itraconazole) is first-line 1
• Disseminated granulomatous disease: Requires prolonged antifungal therapy, potentially lifelong in immunocompromised patients 1

Clinical Pearls and Pitfalls

• Diagnostic pitfall: Coccidioidal granulomas can be mistaken for malignancy, tuberculosis, or sarcoidosis
• Treatment pitfall: Asymptomatic pulmonary granulomas due to coccidioidomycosis do not require treatment once the diagnosis is confirmed 1
• Follow-up consideration: Periodic monitoring of asymptomatic granulomas is recommended to detect any progression 1

Coccidioidomycosis should be considered in the differential diagnosis of granulomatous disease, particularly in patients with travel history to or residence in endemic areas (southwestern United States, parts of Mexico, and Central and South America) 1.