Valley Fever Facts

Coccidioides immitis arthroconidia as would be observed in soil.


Coccidioides immitis spherules as would be observed in tissues.


Geographic distribution of coccidioidomycosis (Valley Fever). Figure from Valley Fever Center for Excellence


Coccidioidomycosis, commonly known as Valley Fever, Desert Rheumatism, Golfers Lung, is a serious disease caused by inhaling spores of Coccidioides immitis or Coccidioides podasii. Coccidioides grows in soil in dry, desert areas of the western United States from Washington to Texas. In particular, most of Arizona and the central valley of California are highly endemic. The spores are spread in dust raised from storms, haboobs, earthquakes, construction, agriculture, digging, off-road vehicles, and any other contact with disturbed, infected soil. While anyone living in, working in, visiting, or traveling through endemic regions is at risk, people in high risk occupations, new to an endemic region, immune suppressed, elderly, children, or pregnant women have been observed to be at higher risk of infection.

Historically, 30-60% of the people living in the endemic regions have demonstrated skin test reactivity to Coccidioides.

Many people, about 60%, who are infected remain relatively asymptomatic and recover without long-term problems. These people historically maintain lifelong immunity to Coccidioides unless they experience immune suppression or very high dose exposures.

Another 40% of cases will be symptomatic forms that result in flu-like symptoms, primarily developing pulmonary disease. Symptoms may include fatigue, cough, chest pain, fever, night sweats, rash, headache, and joint aches. Some patients may develop painful red to brown rashes or bumps on their legs or elsewhere (i.e., erythema nodosum). It is important that symptomatic cases are evaluated by a physician, and that Valley Fever be part of a differential diagnosis for pulmonary infections in endemic regions. Even moderate cases can require months of treatment and may result in weeks of missed school or work. About 40% of symptomatic cases will require hospitalization during the course of disease.  Patients may experience symptoms, in particular lethargy, for a sustained period after recovering from pulmonary infections. Remission is not uncommon after treatment has been discontinued.

In about 1-2% of infections, the disease disseminates. The most common site of spread is in the skin, but Coccidioides may spread to bone, joints, or most other soft tissues. An extremely serious form of disseminated disease is spread to the central nervous system. Disseminated disease can occur months to years after the initial pulmonary infection often, though not always, associated with concurrent disease, surgery, or trauma. While anyone with less severe forms of coccidioidomycosis may develop the disseminated form of the disease, African-Americans, Filipinos, and people with suppressed immune systems are at a greater risk for disseminated disease.

Coccidioidomycosis is diagnosed by physicians based on the history including geography, signs and symptoms, isolation or staining of Coccidioides in biopsies, sputum or lavage fluids, and serological testing. Typically a battery of serological tests are used initially and are then repeated to observe changes in the serological markers over time. Like skin testing, serological tests may not be diagnostic during acute or disseminated forms of coccidioidomycosis or in individuals with compromised immune function. Additionally, serological markers may not be able to identify individuals with prior exposure and immunity to Coccidioides.  Repeated serological testing may be required to diagnose coccidioidomycosis and not all patients will demonstrate antibodies to Coccidioides.

Treatment of coccidioidomycosis is both costly and long term. Not all cases require antifungal treatment. Depending upon the course of the disease and risk factors for serious or disseminated disease, treatment may involve oral antifungals such as fluconazole, itraconazole, and posiconazole. Even moderate cases require many weeks or months of treatment.  In the case of severe or disseminated disease, physicians may administer antifungals intravenously or even directly into the spinal fluid.  Disseminated disease often requires lifetime antifungal treatment.

Long-term consequences may include the formation of cavities or nodules in the chest or fungal abscesses. Such cavities have been found in people with unknown history of coccidioidomycosis and can be misdiagnosed as lung cancer. Additionally, long term consequences of infections involving the central nervous system may lead to lifetime disabilities.

For more information on coccidioidomycosis or Valley Fever, the following resources are available:

Centers for Disease Control and Prevention (CDC)

National Institute for Occupational Safety and Health

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CANDIN® and SPHERUSOL® are trademarks of Nielsen BioSciences, Inc. All other trademarks are the property of their respective owners.


SPHERUSOL is a skin test antigen indicated for the detection of delayed-type hypersensitivity to Coccidioides immitis in individuals with a history of pulmonary coccidioidomycosis.  SPHERUSOL is approved for use in individuals 18-64 years of age.

The use of SPHERUSOL to detect delayed-type hypersensitivity response in a general population with unknown exposure to C. immitis has not been evaluated.

Persons with acute or disseminated coccidioidomycosis may not develop a delayed-type hypersensitivity response to SPHERUSOL.

Persons with immunodeficiency and a history of coccidioidomycosis may not develop a delayed-type hypersensitivity response to SPHERUSOL.



The expected response to SPHERUSOL is a local area of inflammation at the site of the skin test. The reaction is usually dime to quarter size reaching maximum diameter between 24 and 48 hours. Larger accelerated reactions can occur, which may require treatment with local cold compresses and anti-inflammatory medication.

Systemic reactions can occur with skin test antigens and in certain individuals these reactions may be life-threatening or cause death. Emergency measures and personnel trained in their use should be immediately available. Patients should be observed for at least 20 minutes following  the administration of a skin test.

SPHERUSOL should never be given intravenously.


Severe allergic reaction (e.g., anaphylaxis) to SPHERUSOL or any component of SPHERUSOL or history of allergic reaction to other coccidioidins.  

Warnings and Precautions:

Acute hypersensitivity reactions and anaphylaxis have occurred following the administration of other skin test antigens and may occur in individuals following the administration of SPHERUSOL.

Patients receiving beta-blocking drugs may be refractive to the usual dose of epinephrine in cases of hypersensitivity.

Any condition or agent that impairs or attenuates delayed-type hypersensitivity reactions, including infections and use of immunosuppressive drugs, can potentially cause a false negative reaction to SPHERUSOL. 

Adverse Reactions:

The most commonly reported local adverse reactions were itching and swelling (>75%) and pain (>15%) within 7 days of administration.

Drug Interactions:

Corticosteroids and immunosuppressive agents may suppress the response to the skin test.

Use in Specific Populations:

The safety and effectiveness of SPHERUSOL have not been established in pregnant and nursing women, the pediatric population, or individuals > 65 years of age.

This Important Safety Information does not contain all the information needed to use SPHERUSOL safely and effective. Please see Full Prescribing Information for additional information.


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