Valley fever refers to pneumonia caused by a type of fungus called Coccidioides.
Valley fever is also called coccidioidomycosis. The name “valley fever” comes from the fact that the natural habitat of Coccidioides is the southwestern United States, in particular the central California valley.
Valley fever is acquired by breathing Coccidioides spores that are present in the air when soil and dust are disturbed. Valley fever cannot be spread from person to person. It is most often seen in people who live in or travel to California, Arizona, New Mexico, and Texas, where Coccidioides is naturally found. Coccidioides is also found in Mexico and Central America. People who have a higher chance of getting valley fever when exposed to Coccidioides are those with weakened immune systems due to either medical conditions or medications. For example, people who have diabetes, have human immunodeficiency virus (HIV) infection, take high doses of steroids, or are being treated with chemotherapy for cancer are at higher risk of valley fever. Pregnancy is also a risk factor.
Only a small percentage of people who inhale Coccidioides spores actually develop symptoms of valley fever. Symptoms can last weeks to months and include
Cough, which can be a dry cough, a cough with phlegm, or a cough with bloody phlegm
Flu-like symptoms such as muscle pain, joint pain, headache, and fatigue
The diagnosis of valley fever is based on the right clinical symptoms in the right geographical context. Confirmation of the diagnosis is done by testing the blood for Coccidioides antibodies. Sometimes a chest x-ray or computed tomography (CT) scan is helpful to detect changes from pneumonia. Testing of the sputum (phlegm) is rarely done because it is often difficult to get an adequate sample and test results take a long time.
In otherwise healthy people, valley fever usually resolves on its own and does not require treatment. However, all patients diagnosed as having valley fever should follow up with their doctor every 3 to 6 months for up to 2 years to make sure the infection resolves without treatment. Patients whose symptoms do not resolve on their own or who have severe symptoms can be treated with antifungal medications. Treatment, when needed, is usually given for many months.
Centers for Disease Control and Preventionwww.cdc.gov/fungal/coccidioidomycosis
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Sources: Centers for Disease Control and Prevention, Infectious Diseases Society of America
Topic: Infectious Disease
Jin J. Valley Fever (Coccidioidomycosis). JAMA. 2013;310(22):2470. doi:10.1001/jama.2013.280726