Coccidioidomycosis, also known as valley fever, or desert fever, is an infection caused by two fungi, C. immitis and C. posadasii, which grow in the soil and can become airborne when the soil is disturbed by winds, construction, farming and other activities. Infection occurs when fungal spores are inhaled. Coccidioidomycosis—or cocci (COK-see) for short—is the medical term for infection in any part of the body.

Coccidioidomycosis can be a serious illness; however, most cases resolve on their own, especially in people with healthy immune systems. In those with weaker immune systems, it can cause more serious disease. This can include spreading to other organs, including the bones, joints, lymph nodes, kidneys, skin and even the central nervous system, which can be life-threatening if not diagnosed and treated promptly.

Coccidioidomycosis is found mostly in the Southwestern parts of the United States: the central valley of California, Arizona, parts of New Mexico, southern Nevada and Utah, and western Texas. However, newer cases are being seen in northern California, Oregon and Washington, perhaps due to changing climate patterns. Anyone who lives in or visits these areas may be exposed.

The infection is not spread from person to person. Those at higher risk for the disease include: people with HIV especially when CD4 counts are below 250, people 60 years or older, pregnant women, people with diabetes, and people who are Black or Filipino. Sometimes, the disease occurs as a reactivation of an earlier infection.

What are the symptoms and how is it diagnosed?

Most people who are infected with the fungi do not experience symptoms. These cases often resolve on their own with weeks or months. When they do occur, symptoms usually appear within 1–3 weeks of infection and are similar to the flu: fever, tiredness, a productive cough, chest pain, night sweats, chills, headache, muscle aches, and sore throat. If the fungi have spread to other body parts, then additional symptoms are possible.

To diagnose the infection, a health provider will collect fluids from the affected area, such as sputum from the lungs or spinal fluid. Blood and urine tests are also available but can miss the infection. Taken together with current symptoms, a diagnosis can be made.

How is it treated?

People with healthy immune systems who are diagnosed with coccidioidomycosis don’t necessarily require treatment, as the symptoms are usually mild and clear up on their own. For people with weakened immune systems, coccidioidomycosis can progress and cause serious respiratory distress and likely needs to be treated. Most people fully recover with successful treatment.

For mild lung infection or if no symptoms are present but blood test is positive and CD4 count is below 250, oral fluconazole (Diflucan) or itraconazole (Sporanox) at doses of 400 mg a day is recommended. Other antifungals (vorizonazole, posaconazole) may be used if the infection does not respond to the other azoles. Treatment lasts at least 6 months until symptoms resolve and CD4 count stays above 250 while on HIV treatment.

For joint or bone infections, itraconazole is preferred and fluconazole is an alternate option. Treatment lasts at least 12 months until symptoms resolve and CD4 count stays above 250 while on HIV treatment.

For moderate to severe lung disease or for infections outside the lungs but not in the joints, bones or brain, amphotericin B (Fungizone) is recommended. It is given daily through an IV, usually in a hospital, until the patient is feeling better. Azole drugs may also be used. Once symptoms improve, azoles are used or continued. Treatment lasts at least 12 months until symptoms resolve and CD4 count stays above 250 while on HIV treatment.

For spinal or brain infections (meningitis), fluconazole is preferred either by pill or IV. Itraconazole, vorizonazole (Vfend), posaconazole (Noxafil) and amphotericin B are alternate options. Treatment should continue for life because disease returns in 4 out of 5 people who stop treatment.

Immune reconstitution inflammatory syndrome (IRIS)—a condition that causes increased symptoms of an opportunistic infection to happen due to starting or switching HIV treatment— has not been reported with coccidioiodomycosis.

Can it be prevented?

For people living in the Southwest, there is no guaranteed way to prevent coccidioidomycosis from occurring, given that the fungi are found in dust, dirt and soil. Avoid activities that involve long exposure to dirt and soil, such as gardening, farming, or working on excavation sites. Stay indoors during dust storms. Using a face mask during these activities may also help.

A person can also take antifungal medications over time in order to prevent the disease. This is especially true for those with CD4 counts below 250. Preventive treatment may be stopped if the CD4 count stays above 250 for six months or longer while on HIV treatment.

Coccidioidomycosis is more likely to occur in people with HIV with weakened immune systems. Thus, one way to help prevent it from occurring is to keep the immune system healthy—by using HIV meds, reducing stress, eating right, and getting plenty of rest.

Are there any experimental treatments?

If clinical trials for HIV-positive patients with coccidioidomycosis are being conducted, they will most likely be listed on ClinicalTrials.gov, a site run by the U.S. National Institutes of Health. The site has information about all HIV-related clinical studies in the United States. For more info, you can call their toll-free number at 1-800-HIV-0440 (1-800-448-0440) or email contactus@aidsinfo.nih.gov.

Last Reviewed: October 19, 2018