Valley fever (coccidiomycosis)

January 2007     View PDF
Reprinted from University of Arizona’s Valley Fever Center for Excellence, US

How is Valley Fever diagnosed?

A diagnosis of coccidioidomycosis is suspected only if a patient is known to have had exposure to the disease through travel or residence in an endemic area. Diagnosis can be confirmed by (1) microscopic identification of the fungal spherules in an infected tissue, sputum or body fluid sample, (2) growing a culture of Coccidioides immitis from a tissue specimen, sputum or body fluid and (3) detection of antibodies (serological tests specifically for Valley Fever) against the fungus in blood serum or other body fluids. Valley Fever skin tests* (called coccidioidin or spherulin) indicate prior exposure to the fungus, but, because reactivity is lifelong, skin tests are not particularly helpful in diagnosing a current infection. Commonly, a routine chest x-ray will detect Valley Fever cavities in a person with no symptoms and who may be unaware of ever having had Valley Fever. While positive blood test (serological) results almost always mean that a patient has Valley Fever, a third or more of patients with Valley Fever may actually have negative results. Therefore, it may be necessary to repeat the serologies periodically.

* The skin test is currently not available.

Symptoms

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Risk factors for complications