Coccidioidomycosis
Coccidioidomycosis, or valley fever, is a dimorphic fungal infection acquired by inhaling Coccidioides arthroconidia in the southwestern United States, ranging from self-limited pneumonia to disseminated or meningeal disease, diagnosed by culture, histopathology, or serology and treated with fluconazole for symptomatic disease and lifelong fluconazole for meningitis.
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What this article covers
- Overview
A dimorphic fungal pneumonia of the American Southwest: coccidioidomycosis, commonly called valley fever, is caused by Coccidioides, a soil-dwelling dimorphic fungus that exists as a mold in the…
- Epidemiology
Endemic to the southwestern United States and parts of the Americas: Coccidioides is endemic to California's San Joaquin Valley, Arizona, New Mexico, western Texas, northern Mexico, and parts of Central and South America.
- Risk factors
Residence in or travel to an endemic area: the single most important risk factor, given the strict geographic restriction of the organism to specific arid soils.
- Pathophysiology
Inhalation of arthroconidia: infection begins with inhalation of aerosolized arthroconidia from disturbed soil; their small size allows them to reach the distal airways and alveoli.
- Clinical features
Most infections are asymptomatic or mild: the majority of primary infections are subclinical or resemble a mild self-limited upper respiratory illness that resolves without specific treatment.
- Differential diagnosis
Community-acquired bacterial pneumonia: unlike coccidioidomycosis, typical bacterial pneumonia has a more acute onset and improves on empiric antibacterial therapy within days; a protracted febrile…
- Diagnosis
First, the diagnosis is confirmed by mycologic culture, histopathology, or serology, and should be suspected clinically in any compatible illness in an endemic area: diagnosis is often…
- Management
First, decide whether treatment is needed: most immunocompetent patients with mild, uncomplicated primary pulmonary infection can be observed without antifungal therapy, since most infections resolve…
- Complications
Coccidioidal meningitis: the most serious complication, causing chronic basilar meningitis, hydrocephalus, and cranial neuropathies; without lifelong suppressive fluconazole, relapse and death are common.
- Prognosis
Excellent for uncomplicated pulmonary disease: most immunocompetent patients with mild pulmonary infection recover fully without antifungal therapy, and even symptomatic disease treated with fluconazole generally resolves well.
- Prevention
Dust exposure reduction in endemic areas: minimizing outdoor activity during dust storms, using N95 respirators during high-dust occupational exposure, and wetting soil before disturbing it reduce arthroconidia inhalation.
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