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


None of the following information is intended to replace proper diagnosis, treatment, and management by your health care provider.

You should consult with your health care provider about any questions you might have about Valley Fever, coccidioidomycosis, or any other questions you might have about your health.

Valley Fever, or as it is medically known coccidioidomycosis, is a disease caused by inhaling spores of the fungus Coccidioides ("cocci or coccy"). Coccidioides grows in soil in dry, desert areas of the western United States. It has been identified in areas from Washington to Texas with Arizona and the central valley of California being highly endemic. The spores are spread in dust from storms, earthquakes, construction, agriculture, digging, off-road vehicles, and any contact with disturbed, infected soil. Anyone living in, visiting, or traveling through endemic areas are at risk.  People most at risk tend to be new to an endemic region, immune suppressed due to medication, genetics, or other disease, elderly, children, or pregnant women. 

Historically, 30-60% of the people living in the endemic regions were skin test positive to Coccidioides.

Many people, about 60%, who are infected do not have any substantial clinical symptoms. These people historically maintain immunity to Coccidioides, unless they have problems or medications that decrease their immunity.

About 40% of people infected will have symptoms of disease, typically lung disease. Symptoms may include (but not limited to) fatigue, cough, chest pain, fever, night sweats, rash, weight loss, headache, and joint aches. Some patients may develop painful red to brown bumps or rashes on their legs or elsewhere (i.e., erythema nodosum). It is important that anyone with such symptoms be seen by a physician. Even moderate cases can require months of treatment and may result in weeks of missed school or work. Even in moderate cases, remission is not uncommon. Patients may experience symptoms and in particular lethargy for an extended period after treatment.

In about 1-2% of all infections, the disease spreads (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 results from spread to the central nervous system. While anyone with less severe forms of coccidioidomycosis may have the disease spread, African-Americans, Filipinos, people with suppressed immune systems, and pregnant women are at a greater risk for spread.  Appearance of infection in other tissue may occur well after recovery from lung infections. Symptoms of spread to the nervous system includes headaches, neck pain, nausea, back pain or stiffness, and anyone with those symptoms should seek medical care immediately.

Valley Fever is diagnosed by physicians based on: signs and symptoms, your history including where you live, work, or visit, culture of the fungus from body fluids or biopsies, and/or blood tests. It is not unusual for a given case to require multiple blood tests before a diagnosis is made. Blood tests are the main way your doctor will diagnose the disease, though not all people have positive blood test in Valley Fever.  If you live in, work in, visit, or travel through endemic areas and have symptoms, ask your doctor about Valley Fever.

Treatment of coccidioidomycosis is both costly and long term.  Not all people with Valley Fever require treatment, but even mild to moderate cases requires months of treatment with antifungals. Depending your history, symptoms, and risk factors, treatment may involve oral antifungals such as fluconazole, itraconazole, or posiconazole. In the case of severe or disseminated disease, physicians may administer antifungals intravenously or even directly into the spinal fluid.

Long-term consequences may include the formation of cavities or nodules in the chest or fungal abscesses. Such cavities or nodules have been found in people with unknown history of Valley Fever and can look like lung cancers. Additionally, spread to bone, the nervous system, or elsewhere may require life time treatment and have very long term consequences. 

Early diagnosis and proper management of Valley Fever is important.

For more information on coccidioidomycosis or Valley Fever, the following resource is 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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