Valley Fever

Valley Fever (coccidioidomycosis) is a lung infection caused by inhaling tiny fungal spores found in the soil of specific dry, dusty regions, primarily in the southwestern United States. Many people who are exposed never develop symptoms, or they experience mild, flu-like illness that often resolves on its own. However, some individuals can develop more severe or long-lasting forms of the disease.

What is Valley Fever?

Valley Fever, medically known as coccidioidomycosis, is a common fungal infection that affects the lungs. It is caused by inhaling microscopic spores from a specific type of fungus, called Coccidioides, which lives in the soil. This infection is particularly common in dry, dusty areas of the southwestern United States, as well as parts of Mexico and Central and South America.

The Coccidioides fungus thrives in arid (dry) environments. When soil is disturbed by wind, construction, or farming, the fungal spores can become airborne. If you breathe in these spores, they can settle in your lungs and cause an infection. Valley Fever is not contagious, meaning it cannot spread from person to person or from animals to people. The infection only occurs when someone inhales the fungal spores directly from the environment. While it typically affects the lungs, in rare cases, the fungus can spread to other parts of the body, leading to a more serious condition called disseminated Valley Fever.

Symptoms

Many people who are exposed to the Valley Fever fungus never develop any symptoms at all, or they experience very mild, flu-like symptoms. When symptoms do occur, they usually appear 1 to 3 weeks after exposure and can include fever, cough, fatigue, and muscle aches. These symptoms often resolve on their own within weeks to months.

About 3 out of 5 people (60%) infected with Valley Fever do not show any symptoms. For those who do develop symptoms, they are often mild and similar to the common cold or flu. Common symptoms include fever, cough, chest pain, fatigue (tiredness), headache, muscle aches, and joint pain. Less common symptoms can include a rash, which may appear as red bumps or lesions, especially on the shins. In a small number of cases, the infection can become severe or spread beyond the lungs. This disseminated (widespread) form of Valley Fever can cause more serious symptoms, such as skin lesions or sores that don't heal, painful swelling in joints, bone pain, and even meningitis (inflammation of the membranes surrounding the brain and spinal cord).

Causes & risk factors

Valley Fever is caused by inhaling tiny spores from the Coccidioides fungus, which lives in the soil of specific regions. You are at higher risk if you live in or travel to these endemic areas and engage in activities that disturb the soil, such as construction or farming. Certain medical conditions or medications that weaken your immune system also increase your risk.

The sole cause of Valley Fever is breathing in the Coccidioides fungal spores. These spores become airborne when dry soil is disturbed. This can happen during activities like digging, construction work, farming, or even during dust storms. Several factors can increase your risk of developing Valley Fever or a more severe form of the disease. Living in or traveling to areas where the fungus is common, such as Arizona, California's San Joaquin Valley, Nevada, New Mexico, Texas, and Utah, is the primary risk factor. People who work outdoors in these areas, like construction workers, archaeologists, and agricultural workers, are at higher risk due to increased exposure to disturbed soil. Additionally, certain groups are more likely to develop severe Valley Fever. This includes people with weakened immune systems due to conditions like HIV/AIDS, organ transplants, or medications such as corticosteroids or chemotherapy. Pregnant individuals, especially in their third trimester, and people of Filipino and African American descent also have a higher risk of developing severe or disseminated forms of the infection.

How it's diagnosed

Diagnosing Valley Fever typically involves blood tests that look for antibodies produced by your immune system in response to the fungus. Your doctor may also use imaging tests, such as a chest X-ray or CT scan, to check for lung changes. In some cases, a tissue biopsy or culture may be needed to confirm the diagnosis.

If your doctor suspects Valley Fever, they will likely start with a physical exam and ask about your symptoms and travel history. The most common diagnostic tool is a blood test that detects antibodies (proteins made by your immune system) against the Coccidioides fungus. A positive antibody test usually indicates an active or recent infection. To assess the extent of the infection, especially in the lungs, your doctor may order imaging tests. A chest X-ray can show signs of pneumonia or other lung abnormalities. A CT (computed tomography) scan may provide a more detailed view of the lungs and surrounding areas. If the infection is severe or has spread, other imaging tests might be used. In some complex cases, or if initial tests are inconclusive, a doctor might perform a tissue biopsy. This involves taking a small sample of affected tissue, such as from the lungs or skin, and examining it under a microscope or culturing it (growing the fungus in a lab) to confirm the presence of Coccidioides. Sputum (mucus coughed up from the lungs) can also be cultured.

Treatment options

Treatment for Valley Fever depends on the severity of your symptoms and your overall health. Many mild cases do not require specific treatment, as the infection often resolves on its own. For more severe or persistent infections, or if you have a weakened immune system, antifungal medications are typically prescribed to help your body fight the fungus.

If you have mild Valley Fever symptoms and are otherwise healthy, your doctor may recommend watchful waiting. This means monitoring your symptoms without medication, as the infection often clears up naturally over several weeks to months. Rest and pain relievers can help manage discomfort during this time. For more severe cases, or if symptoms persist for more than a few months, antifungal medications are usually prescribed. The most common antifungal drugs used are fluconazole and itraconazole. These medications work by stopping the growth of the fungus. Treatment can last for several months, or even longer, depending on how well you respond and if the infection has spread. If the Valley Fever has spread beyond the lungs (disseminated disease) or affects the brain and spinal cord (meningitis), more aggressive treatment is needed. This might involve different types of antifungal medications, sometimes given intravenously (through a vein), and often for a much longer duration, potentially for life in some cases. Your doctor will determine the best treatment plan based on your specific condition.

Recovery & outlook

Most people with mild Valley Fever recover fully, often without specific treatment, though fatigue can sometimes last for several months. For those with more severe or disseminated disease, recovery can be longer and require extensive antifungal therapy. While most people recover, some may experience long-term effects or require ongoing medication to prevent recurrence.

For the majority of people with Valley Fever, especially those with mild or no symptoms, the outlook is very good. The infection typically resolves completely, and most individuals develop immunity that protects them from future infections. However, even after symptoms disappear, some people report lingering fatigue that can last for several months. If the infection is more severe or has spread to other parts of the body, the recovery process can be more challenging and prolonged. Disseminated Valley Fever is a serious condition that requires long-term antifungal treatment, sometimes for years or even for life. Without proper treatment, disseminated disease can be life-threatening. Even after successful treatment, there is a small chance of the infection recurring, especially in individuals with weakened immune systems. Regular follow-up with your doctor is important to monitor your recovery and address any potential long-term complications or relapses. Your doctor will guide you on the expected course of your recovery based on the severity of your infection.

When to see a doctor

You should see a doctor if you develop flu-like symptoms that do not improve within a week or two, especially if you live in or have recently traveled to an area where Valley Fever is common. Seek immediate medical attention for severe symptoms like shortness of breath, severe chest pain, confusion, or a stiff neck, as these could indicate a more serious form of the infection.

It is important to contact your doctor if you experience persistent flu-like symptoms, such as fever, cough, and fatigue, that last longer than a week or two, particularly if you have been in a Valley Fever endemic area. Early diagnosis can help ensure you receive appropriate care if needed. Seek prompt medical attention if you develop any of the following more severe symptoms: shortness of breath, severe chest pain, skin lesions that are new or not healing, painful and swollen joints, or unexplained weight loss. These could be signs that the infection is more serious or has spread beyond the lungs. Emergency medical care is necessary if you experience symptoms that suggest the infection has spread to your brain or spinal cord. These include a stiff neck, severe headache, confusion, sensitivity to light, or seizures. These symptoms could indicate Valley Fever meningitis, a life-threatening condition that requires immediate treatment.

Frequently asked questions

Can Valley Fever be prevented?

There is currently no vaccine to prevent Valley Fever. The best way to reduce your risk is to avoid inhaling the fungal spores. If you live in or visit areas where Valley Fever is common, try to avoid dusty areas, especially during windy conditions or when soil is being disturbed. Wearing a mask, such as an N95 respirator, can offer some protection if you are in a very dusty environment or have a weakened immune system.

Is Valley Fever contagious?

No, Valley Fever is not contagious. You cannot catch it from another person or from an animal. The infection is only acquired by inhaling the fungal spores directly from the environment, typically from disturbed soil in endemic regions.

How long does Valley Fever last?

For most people with mild symptoms, Valley Fever typically resolves on its own within a few weeks to several months. However, some individuals may experience lingering fatigue for months. If the infection is severe or has spread, treatment with antifungal medications can last for many months, years, or even a lifetime.

Can Valley Fever come back after treatment?

While most people develop immunity after an initial infection, it is possible for Valley Fever to recur, especially in individuals with weakened immune systems. In some cases, long-term antifungal medication may be prescribed to prevent the infection from returning.

Are there long-term effects of Valley Fever?

Many people recover fully without long-term effects, though fatigue can persist for months. In severe cases, especially if the infection spreads to other organs, Valley Fever can cause lasting damage to the lungs, bones, joints, or central nervous system. Disseminated disease often requires ongoing medical management.

Who is most at risk for severe Valley Fever?

Individuals with weakened immune systems (due to conditions like HIV/AIDS, organ transplants, or certain medications), pregnant people (especially in their third trimester), and those of Filipino and African American descent are at higher risk for developing severe or disseminated forms of Valley Fever. People with diabetes may also be at increased risk.

Sources

• MedlinePlus — Valley Fever
• Mayo Clinic — Valley Fever
• Cochrane Library — Valley Fever