Valley fever

Learn about symptoms and treatment for this lung infection caused by fungi found in the soil of desert regions.

Update Date: 20.09.2025

Overview
Symptoms
When to see a doctor
Causes
Risk factors
Complications
Prevention
Diagnosis
Treatment
Preparing for your appointment

Overview

Valley fever is a fungal infection. Coccidioides (kok-sid-e-OI-deze) organisms are the cause. Also called San Joaquin Valley fever, it can cause symptoms such as a fever, cough and tiredness.

Two coccidioides fungi species cause valley fever. These fungi are commonly found in soil in specific areas. Farming, construction, wind and anything else that disturbs the soil may send the fungi's spores into the air.

People can then breathe the fungi into their lungs. The fungi can cause valley fever, also known as acute coccidioidomycosis (kok-sid-e-oi-doh-my-KOH-sis). Valley fever may be mild and get better without treatment. People who have a serious valley fever illness may need antifungal medicines.

Symptoms

Symptoms of coccidioidomycosis depend on the form of the infection. Valley fever is the first, also called acute, stage of coccidioidomycosis infection. This acute illness can become more serious. More serious illness includes long-term, called chronic, coccidioidomycosis and coccidioidomycosis that spreads, called disseminated coccidioidomycosis.

Acute coccidioidomycosis, also called valley fever

The first, also called acute, form of coccidioidomycosis often has few or no symptoms. Symptoms may start 1 to 3 weeks after contact with the fungus.

Symptoms tend to be like flu symptoms. Symptoms can range from minor to serious, including:

  • Fever.
  • Cough.
  • Tiredness.
  • Shortness of breath.
  • Chest pain when breathing in.
  • Night sweats.
  • Headache.
  • Joint pain, mainly in the ankles, knees and wrists.
  • Rash.

For people who get symptoms, especially serious ones, the course of the illness varies from person to person. It can take months to fully recover. Tiredness and joint aches can last even longer.

Chest X-ray is often not typical and looks like pneumonia.

Ongoing, called chronic, coccidioidomycosis

If the first coccidioidomycosis infection doesn't clear up all the way, it may move to an ongoing form of pneumonia. This complication is most common in people with weakened immune systems.

Symptoms include:

  • Low-grade fever.
  • Weight loss.
  • Cough. Coughing may cause blood-tinged mucus.
  • Chest pain.
  • Areas of infection, called nodules, cavities or scarring in the lungs.

Coccidioidomycosis that spreads, called disseminated

This most serious form of the condition isn't common. It happens when the infection spreads, called disseminates, from the lungs to other parts of the body. It mainly spreads to the skin, bones, liver, brain, heart, and the membranes that protect the brain and spinal cord, called the meninges.

Symptoms of disseminated disease depend on the body parts affected. They may include:

  • Nodules and skin sores that are more serious than the rash that sometimes happens with the first form of the infection.
  • Painful sores in the spine, legs and knees or other bones.
  • Painful, swollen joints, mainly in the knees or ankles.
  • An infection of the membranes and fluid around the brain and spinal cord, called meningitis.

When to see a doctor

Seek medical care if you have symptoms of valley fever if you are older than 60, have a weakened immune system, are pregnant, or you're Filipino or African. (5p3) Seeking care is most important if you:

  • Live in or have recently traveled to an area where this illness is common.
  • Have symptoms that aren't getting better.

Be sure to tell your healthcare professional if you've traveled to a place where valley fever is common.

Causes

Breathing in spores of certain fungi causes valley fever. The fungi that cause valley fever are Coccidioides immitis and Coccidioides posadasii. They live in the soil in parts of Arizona, California, Nevada, Utah, New Mexico, Texas and Washington. The fungi also are in northern Mexico and Central and South America.

The wind carries the tiny spores. Once inside the lungs, the spores grow and turn into the main form of the fungus in the body.

Risk factors

Risk factors for valley fever include:

  • Being in an area where the fungi are common. Anyone who breaths in the spores that cause valley fever is at risk of infection. People who live in areas where the fungi are common and spend time outdoors are at greater risk. Also, people who have jobs that expose them to dust in areas where the fungi are common are most at risk. Jobs include construction, road and farm work, and ranching. People who study the past by digging up relics, called archaeologists, and people training for the military also have a higher risk.
  • Being of certain races. Experts don't know why, but people whose families are from the Philippines and Africa are more likely to get serious fungal infections from this condition.
  • Being pregnant. Pregnant people are more likely to get serious infections when they get the infection during the third trimester or right after their babies are born.
  • Having a weakened immune system. Some people with weakened immune systems are at higher risk of serious complications. This includes people living with AIDS or those being treated with steroids or medicines to keep from rejecting donor organs. People who take certain medicines for conditions in which their immune systems attack their bodies have a higher risk of infection. These conditions are called autoimmune conditions. They include rheumatoid arthritis and Crohn's disease.
  • Having diabetes. People with diabetes may have a higher risk of certain lung infections.
  • Being older. Older adults are more likely to get valley fever. This may be because their immune systems get weaker with age or because they have other medical conditions.

Complications

Complications of coccidioidomycosis may include:

  • Serious pneumonia. Most people who have coccidioidomycosis-related pneumonia get better without complications. Others, such as people whose families are from the Philippines or Africa and those with weakened immune systems may get very ill.
  • Burst lung cavities. A small percentage of people get thin-walled nodules, also called cavities, in their lungs. Many nodules and cavities go away without causing any issues. But some cavities may burst. This causes chest pain and trouble breathing. Treatment for a burst lung nodule might involve putting a tube into the space around the lungs to remove the air or surgery to fix the damage.
  • Disseminated disease. This is the most serious complication of coccidioidomycosis. It's not common. If the fungus spreads, called disseminates, through the body, it can cause serious health issues. These may include skin sores, joint pain, swelling and irritation, called inflammation. It also can cause an infection, called meningitis, of the membranes and fluid covering the brain and spinal cord. Meningitis may be fatal if not treated.

Prevention

There is no vaccine to prevent valley fever.

If you live in or visit areas where valley fever is common, take steps to prevent infection. The dry season following a rainy season is when the chance of infection is highest.

Try these tips:

  • Wear a mask.
  • Stay clear of very dusty areas, such as construction sites.
  • Stay inside during dust storms.
  • Wet the soil before digging in it. Stay away from the soil if you're at higher risk of infection.
  • Keep doors and windows tightly closed.
  • Clean skin injuries with soap and water.

Diagnosis

To diagnose valley fever, your healthcare professional looks at your medical history and your symptoms. Valley fever is hard to diagnose based on symptoms because symptoms are often mild and like those of other illnesses. Even on a chest X-ray, valley fever can look much like other lung infections such as pneumonia.

To diagnose valley fever, healthcare professionals may order one or more of the following tests:

  • Sputum smear or culture. These tests check a sample of the matter that comes up while coughing, called sputum, for coccidioides organisms.
  • Blood tests. A blood test can show antibodies against the fungus that causes valley fever.

Other tests may include:

  • Imaging tests. To look for pneumonia from valley fever, you may have imaging tests, such as a CT scan, MRI or chest X-ray.
  • Lung biopsy. A healthcare professional takes a sample of lung tissue for study under a microscope.
  • Skin test. This may show that you've had valley fever in the past and can't get it again, called immunity.

Treatment

Valley fever most often clears up on its own. Some people need medicines.

Antifungal medicines

A healthcare professional may prescribe an antifungal medicine. This medicine can treat symptoms that don't improve, last a long time or get worse. You also might take this medicine if you're at a higher risk of complications or have infection that lasts, called chronic, or spreads, called disseminated.

The antifungal medicine fluconazole (Diflucan) most often treats all but the most-serious forms of coccidioidomycosis disease. Another treatment is itraconazole (Sporanox, Tolsura).

Antifungal medicines can have serious side effects. Side effects tend to go away once you stop taking the medicine. Side effects of fluconazole and itraconazole may include upset stomach, vomiting and loose stools. Side effects of fluconazole also may include hair loss, dry skin, dry mouth and chapped lips.

An antifungal medicine most often given as a pill may treat more serious infection. These include amphotericin B (Abelcet, Ambisome), voriconazole (Vfend), posaconazole (Noxafil) and isavuconazonium (Cresemba).

For many people, having valley fever once means they can't get it again. But for people with weakened immune systems, the infection may come back. Even if you don't have treatment, your healthcare professional may watch you for complications or relapse for at least a year.

Preparing for your appointment

See your healthcare professional if you get symptoms of valley fever and are in or have just come back from an area where this condition is common.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do before you go.

Make a list of:

  • Your symptoms, and when they began.
  • When you've traveled recently, and where.
  • Key medical information, including other conditions you have and any medicines, vitamins or supplements you take, including doses.
  • Questions to ask your healthcare professional.

Questions to ask about valley fever might include:

  • What's the most likely cause of my symptoms?
  • What tests do I need?
  • What treatment do you suggest, if any?
  • I have these other health conditions. How can I manage these conditions together?
  • Am I at risk of long-term complications from this condition?

What to expect from your doctor

Your healthcare professional may ask you questions, including:

  • Have your symptoms gotten worse over time?
  • Does your work or what you do for fun involve spending time in dusty outdoor places?
  • Are you pregnant?

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