Coccidioidomycosis is an infection, usually of the lungs, caused by the fungus Coccidioides immitis or Coccidioides posadasii.
The infection is caused by inhaling spores of the fungus.
If mild, the lung infection causes flu-like symptoms and sometimes shortness of breath, but the infection may worsen and spread throughout the body, causing various symptoms.
The diagnosis can be confirmed by identifying the fungi in samples of infected materials examined under a microscope or cultured.
Treatment is with antifungal medications.
(See also Overview of Fungal Infections.)
The spores of Coccidioides are present in soil in the southwestern United States, the central valley of California, parts of New Mexico, Texas west of El Paso, northern Mexico, and parts of Central America and Argentina. They also can be found in Utah, Nevada, and southcentral Washington.
Coccidioidomycosis causes about 15 to 30% of cases of community-acquired pneumonia (a lung infection that develops in people who are not patients in a hospital) in metropolitan areas of Arizona such as Tucson and Phoenix.
In the United States, 20,003 cases of coccidioidomycosis were reported in 2019.
Coccidioidomycosis is acquired by inhaling spores. Spores are present in soil and can become airborne when the soil is disturbed and dust travels downwind. Farmers and others who work with or are exposed to disturbed soil are most likely to inhale the spores and become infected. People who become infected while traveling may not develop symptoms until after they go home.
Coccidioidomycosis occurs in two forms:
Acute primary coccidioidomycosis is a mild lung infection. The infection disappears without treatment. This form accounts for most cases.
Progressive coccidioidomycosis is a severe, rapidly worsening infection. The infection spreads from the lungs throughout the body and is often fatal.
Risk factors for progressive coccidioidomycosis
Progressive coccidioidomycosis is uncommon in otherwise healthy people. Risk factors include
Medications that suppress the immune system (immunosuppressants)
Older age
Being in the second or third trimester of pregnancy or postpartum (just had a baby)
Race or ethnicity (Filipino, Black, American Indian, Hispanic, or Asian)
Symptoms of Coccidioidomycosis
Most people with acute primary coccidioidomycosis have no symptoms. If symptoms develop, they appear 1 to 3 weeks after people are infected. Symptoms are usually mild and often flu-like. They include a cough, fever, chills, chest pain, and sometimes shortness of breath. The cough may produce sputum. Occasionally, when lung infection is severe, spaces may form in the lungs and people may cough up blood.
People with progressive coccidioidomycosis may develop symptoms weeks, months, or even years after the initial infection. Symptoms include mild fever and loss of appetite, weight, and strength. The lung infection may worsen, usually only in people with a weakened immune system. It may cause increased shortness of breath and sometimes blood in the sputum.
Coccidioidomycosis may also spread from the lungs to the skin and other tissues. If infection spreads to the skin, people may have one sore or many. Joints may become swollen and painful. Deep infections sometimes break through the skin, causing an opening that infected material drains through.
With either form of coccidioidomycosis, some people have an allergic reaction to the fungus, which can cause joint pain, conjunctivitis, tender red or violet bumps (nodules) under the skin (called erythema nodosum), or patches of red, raised skin that often look like targets (erythema multiforme).
Coccidioides can also infect the brain and the tissues covering the brain (meninges), causing meningitis. This infection is often chronic, causing headaches, confusion, loss of balance, double vision, and other problems. Untreated meningitis is always fatal.
Diagnosis of Coccidioidomycosis
Blood tests
A chest x-ray
Examination and culture of a sample of blood or other tissue
A doctor may suspect coccidioidomycosis if people develop symptoms after living in or recently traveling through an area where the infection is common.
Blood tests to detect antibodies to the fungus (serologic tests) and a chest x-ray are typically done. In people with a healthy immune system, blood tests can usually detect these antibodies if coccidioidomycosis is present. Chest x-rays usually show characteristic abnormalities. These findings help doctors make the diagnosis.
A test that detects antigens (proteins released by the fungus) in urine may also be useful.
To identify the fungus and thus confirm the diagnosis, doctors may examine samples of blood, sputum, pus, cerebrospinal fluid, or other infected tissue under a microscope or send them to a laboratory to be cultured. Because culturing Coccidioides may take up to 3 weeks, doctors typically rely on the blood tests and chest x-ray.
A test to identify the fungus' genetic material (its DNA) can be done on samples taken from the throat and lungs, but this test is not widely available.
Treatment of Coccidioidomycosis
Antifungal medications
Acute primary coccidioidomycosis
Progressive coccidioidomycosis
People with a weakened immune system must take medications for years, often for life.
If bone is infected or if the infection results in spaces in the lung, surgery may be necessary.
