Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at November 23, 2016

Coccidioidomycosis is often called valley fever because there have been several widely-publicized outbreaks that have occurred in valley regions. Though most people can overcome this fungal infection on their own, it can cause severe issues among immunocompromised people. 


Definition & Facts

Coccidioidomycosis is a fungal infection that occurs after a patient inhales microscopic spores of the Coccidioides fungus. After inhaling the fungus, patients suffer from many symptoms that can range from mild to severe. Though valley fever is primarily a lung infection, it can also affect other areas of the body.

Known habitats of this fungus include certain areas in the United States, Mexico, and South America, but it may be possible for people in other regions to get sick. Over a third of all coccidioidomycosis cases occur in the Central Valley of California which is where the alternative name for this illness comes from. 

Symptoms & Complaints

Roughly 60 percent of all people infected with the Coccidioides fungal spores will not display any symptoms. Those who do get the symptoms of valley fever exhibit a wide range of issues.

The most common symptoms are typical of respiratory infections such as pneumonia or the flu. Patients can develop a fever, have difficulty breathing, acquire a severe cough, and feel short of breath.

Other symptoms may include headaches, rashes, aching muscles, joint pains, and night sweats. These symptoms appear about one to three weeks after fungal exposure, and they usually only last a month or so.

In some cases, the unpleasant symptoms can linger for a lifetime. Chronic Coccidioidomycosis is more likely to occur in the rare instances when the infection travels throughout the body. Once it gets out of the lungs, the infection can show up in the brain, bones, or other internal organs, and it typically causes inflammation and infections.

The spread of the infection can result in life-threatening abscesses, osteomyelitis, and meningitis. In very rare cases, Coccidioides can infect a scratch on the skin and turn into a lesion.


The Coccidioides fungus that causes valley fever has a very precise infection mechanism. This fungus can only grow after rain has dampened a large area of soil. It then grows into long filaments. When the soil starts to dry out, microscopic cells of the fungus break off and start traveling along air currents.

If a human inhales the spores or gets them into a scratch, the damp, warm environment of the human body causes the spores to start growing. They enlarge into cells that produce more infective spores that then travel throughout the rest of the body.

Valley fever is particularly common in areas with a lot of bare soil that is not covered by trees or grass. Though Coccidioides fungi can grow in damp soil, they can spread much easier in arid land. Therefore, farming areas and mining areas with a dry climate are most likely to spread Coccidioides to humans.

Coccidioidomycosis most frequently spreads through dust inhalation, but it is also possible to get it from an organ transplant, inhaling spores that are released from an open wound infected with Coccidioides, or inhaling spores from an object coated in spores.

Diagnosis & Tests

Because Coccidioidomycosis has symptoms very similar to other respiratory infections, there is a great danger of misdiagnosis. Many patients are mistakenly diagnosed with pneumonia at first, but typical pneumonia treatments cannot manage Coccidioidomycosis.

Patients are more likely to get a proper diagnosis if their doctor takes a complete patient history and learns that they have recently been in an area that is going through a Coccidioides outbreak. A doctor may suspect that a patient has Coccidioidomycosis if they are experiencing respiratory issues along with other key symptoms of the illness.

In addition to a physical examination, chest computed tomography (CT) scans can be used to detect the cysts or lung opacification that can happen among patients with Coccidioidomycosis. However, a diagnosis of valley fever cannot be confirmed until lab tests show either the presence of Coccidioides spores or the unique antigens that the body creates to fight back against the fungus.

The simplest way to test for these spores and antigens is by examining a blood sample from the patient. It is also possible to do a tissue biopsy or look at a sputum sample to see the spores or antigens.

Treatment & Therapy

In most cases, Coccidioidomycosis goes away on its own without resulting in any severe symptoms. The treatment for mild cases is similar to the treatment for the flu. Patients just need to get plenty of rest, drink a lot of fluids, and take over-the-counter pain relievers for any aching. It is more likely to cause troubling or long lasting symptoms among the elderly, people with HIV, and others with weakened immune systems.

Only about five percent of all people infected with Coccidioidomycosis will need medical treatment. The first line of treatment is a basic oral antifungal medication such as fluconazole or itraconazole. This is often extremely effective at getting rid of the spores. If the infection still persists, intravenous therapy with the antifungal amphotericin B will be recommended. Treatments with antifungal medications normally require consistent does for three to six months. Those with severe lung infections may need medical monitoring in a hospital to ensure that their condition does not worsen. 

Prevention & Prophylaxis

The risk for valley fever is very low in most parts of the world though caution should be exercised when traveling to dusty areas. If possible, one should should try to avoid breathing in dust or visiting dusty places like construction areas.

If one cannot avoid going to dusty areas or engaging in activities that require close contact with dirt, wearing a face mask can help prevent spore inhalation. When dust storms appear, one should remain indoors with the windows closed. Any skin wounds should be thoroughly cleaned and covered with a bandage to prevent infections.