What You Should Know About
Valley Fever (Coccidioidomycosis)
In most parts of the United States there are fungi that live in the soil. In the midwest that fungus is called histoplasma. Inhalation of the fungus can produce a lung disease called histoplasmosis. A similar fungus, called coccidioides immitis lives in the desert soil of southern Arizona, northern Mexico, and parts of southern California. Spores of this fungus are carried with the wind, and when inhaled, can cause a disease that is commonly called valley fever. About 60% of the time, the inhaled spores do not cause any clinical illness. The other 40% of the time, a flulike illness develops about two weeks after the inhalation. In most individuals who have a normal immune response, the symptoms of cough, low-grade fever, and malaise go away after a week or so, and are soon forgotten. For a small minority of people with impaired immunity, the fungus can spread through the body, and produce a life threatening illness.
Diagnosis and Treatment
There is nothing that is very distinctive about a valley fever infection. It may feel like a viral flu episode. During the acute illness it may be possible to culture the fungus from the sputum. Chest X-rays may show a pneumonia that looks similar to a bacterial pneumonia. As mentioned above, for most people with normal immunity, no anti-fungal treatment is usually required. If valley fever is suspected as the cause of the illness, blood tests may be done, which demonstrate antibodies to the fungus and confirm a diagnosis of valley fever.
In about 5 to 10% of cases, the chest x-ray does not clear completely. A small scar or nodule may be present where the pneumonia previously existed. Unfortunately, it is not always possible to tell this nodule from a mass that is created by a lung cancer. Many times a chest X-ray is taken several years after a valley fever pneumonia episode, and the nodule is confused with a cancer. At that time, the blood test is no longer positive, and it may be necessary to obtain a piece of tissue from the nodule to rule out cancer. A similar scar to the nodule is what is called a cavity in the lung. This is a hole that is the same as a nodule except that it has hollowed out, leaving only a rim of tissue around a hole in the lung. Cavities sometimes bleed, and become infected easily. In those instances, surgical removal may be necessary.
As a general rule, anti-fungal medicines are only used when it appears that the infection will overwhelm the immune defense of the patient. Traditionally the most potent anti-fungal has been a drug that is given by IV, called amphotericin. This drug has many side effects, especially involving the kidney. Several anti-fungals in pill form are now available. They are not as effective as antibiotics are in treating bacterial infections, but can be effective in controlling the fungal infection.
Where to Get Additional Information
For more information, try these online resources.
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