Valley fever, also known as coccidioidomycosis, is a fungal infection that is caused by inhaling the spores of the fungus Coccidioides immitis or Coccidioides posadasii. This fungus is found in soil in certain regions, including the southwestern United States and parts of Central and South America.

Most people who are exposed to the fungus do not develop symptoms of the disease. However, some people can develop flu-like symptoms such as fever, cough, chest pain, and fatigue. In some cases, the infection can spread to other parts of the body, such as the skin, bones, or joints. People who have weakened immune systems or underlying medical conditions such as diabetes or lung disease are at increased risk of developing severe or disseminated valley fever.

Diagnosis of valley fever typically involves a physical exam, medical history review, and laboratory tests such as blood tests, chest X-rays, or fungal cultures. Treatment for valley fever usually involves antifungal medications, such as fluconazole or itraconazole, which can help to clear the infection and alleviate symptoms. In some cases, hospitalization may be necessary for more severe or disseminated cases of the disease.

Preventive measures for valley fever include avoiding exposure to dust and soil in areas where the fungus is present, wearing a mask during dust storms or construction activities, and keeping windows and doors closed during windy weather. It is important to seek medical attention if any symptoms of valley fever are present, especially if they persist or worsen over time.

Valley fever is caused by a person inhaling spores of certain fungi. The fungi that cause valley fever — Coccidioides immitis or Coccidioides posadasii — live in the soil in parts of Arizona, Nevada, Utah, New Mexico, California, Texas and Washington. It's named after the San Joaquin Valley in California. The fungi can also often be found in northern Mexico and Central and South America.

Like many other fungi, coccidioides species have a complex life cycle. In the soil, they grow as a mold with long filaments that break off into airborne spores when the soil is disturbed. A person can then inhale the spores.

The spores are extremely small and can be carried far by the wind. Once inside the lungs, the spores reproduce, continuing the disease cycle.

There is no vaccine to prevent valley fever.

If you live in or visit areas where valley fever is common, take common-sense precautions, especially during the summer months when the chance of infection is highest.

Consider these tips:

• Wear a mask.
• Avoid very dusty areas, such as construction sites.
• Stay inside during dust storms.
• Wet the soil before digging in it, or avoiding soil if you're at higher risk of infection.
• Keep doors and windows tightly closed.
• Clean skin injuries with soap and water.

Valley fever usually involves supportive care and sometimes medications.

Rest

Most people with acute valley fever don't require treatment. Even when symptoms are severe, the best therapy for otherwise healthy adults is often bed rest and fluid intake. Still, doctors carefully monitor people with valley fever.

Antifungal medications

If symptoms don't improve or become worse, or you're at increased risk of complications, your doctor may prescribe an antifungal medication, such as fluconazole. Antifungal medications are also used for people with chronic or disseminated disease.

The antifungal drugs fluconazole (Diflucan) or itraconazole (Sporanox, Onmel, Tolsura) are generally used for all but the most serious forms of coccidioidomycosis disease.

All antifungals can have serious side effects. But these side effects usually go away once the medication is stopped. Possible side effects of fluconazole and itraconazole are nausea, vomiting, stomach pain and diarrhea.

More serious infection may first be treated with an intravenous antifungal medication such as amphotericin B (Abelcet, Ambisome, others).

Three newer medications — voriconazole (Vfend), posaconazole (Noxafil) isavuconazonium sulfate (Cresemba) — may also be used to treat more-serious infections.

Antifungals control the fungus, but sometimes don't destroy it, and relapses may occur. For many people, a single bout of valley fever results in lifelong immunity. But the disease can be reactivated, or you can be reinfected if your immune system is significantly weakened.