Coccidioidomycosis (Valley Fever)

Frequently Asked Questions (FAQs)

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What is Valley Fever?

Valley Fever (medical name coccidioidomycosis [kok-sid-e-oy-do-my-co-sis] or "cocci" for short) is an infection in the lungs caused by a fungus (scientific name Coccidioides immitis or Coccidioides posadasii) that grows in the soil in the southern and central parts of California, Arizona, and portions of New Mexico, Texas, Nevada and Utah. Valley Fever is also found in parts of Mexico, Central and South America. These areas where the fungus grows in the soil are called "endemic."

Who can get Valley Fever?

Anyone who lives, visits, or travels through the areas where the fungus grows in the soil may acquire Valley Fever. People working in certain occupations such as construction, excavation, agriculture, archaeological digging and other occupations which disturb soil in endemic areas may be at increased risk of exposure. Military personnel training in these areas are also at risk. Persons who pursue recreational activities such as biking or driving ATVs or 4-wheel drive vehicles in the desert may be at increased risk. Various domestic animals such as dogs and horses as well as wild animals are also susceptible.

endemic areas

Source: CDC

How do you get Valley Fever?

Valley Fever is acquired by breathing in airborne spores of the fungus Coccidioides. The spores are carried in dust particles from the soil by the wind when the desert soil is disturbed. Valley Fever is NOT spread from human to human, or animal to animal, or animal to human, or human to animal. The spores change form in the body and are not contagious.

What is the connection between the weather and Valley Fever?

Although blowing dust may carry fungal spores throughout the year, peak season for Valley Fever is from June through August and October through November. Rainfall, temperature, and wind conditions may also affect the risk of getting Valley Fever.

How many people in Arizona get Valley Fever? How many die from it?

See the Surveillance and Reports pages for more information on the number of reported cases and deaths from Valley Fever.

What are the symptoms of Valley Fever?

Most cases (60%) have no symptoms or only very mild flu-like symptoms and do not see a doctor. The most common symptoms are fatigue, cough, fever, sweating at night, loss of appetite, chest pain, muscle and joint aches, particularly of the ankles and knees. There may also be a rash that resembles measles or hives, but appears more often as tender red bumps on the shins or forearms.

Patients with chronic Valley Fever infections have long lasting symptoms such as low grade fever, weight loss, cough, chest pain and coughing up blood. These symptoms are often slow to appear and resemble tuberculosis when coupled with x-ray findings.

How long does it take for symptoms to appear?

Symptoms usually appear within 7-28 days after breathing in fungal spores.

How long do symptoms last?

Most people have no symptoms. Those that do can have symptoms for weeks or even months. Fatigue and joint aches can last for a long time. People with chronic or disseminated disease may be ill for years.

What does the rash caused by Valley Fever look like?

Valley Fever can cause two different types of rashes: erythema nodosum and erythema multiforme. Erythema nodosum involves painful or tender red bumps which may change color to bluish or brown. Erythema multiforme is a red raised rash which may have blisters or bumps. Other diseases can also cause these rashes and having these rashes does not necessarily mean you have Valley Fever. The rashes are part of the body’s reaction to infection. See the pictures of each rash below. The fungus can also cause skin infections, which look different from these rashes.

Erythema Nodosum
erythema nodosum

Source: CDC

Erythema Multiforme
erythema multiforme

Source: James Heilman/Wikipedia

What is dissemination?

Dissemination is the spread of the fungal infection from the lungs to other parts of the body. The most common sites of dissemination are skin, bones, joints and brain meninges (the tissue layers around the brain). Infection of the brain meninges can be deadly.

What is the risk of dissemination?

While anyone can contract Valley Fever, there are differences in risk of disseminated disease among people. Men have a higher rate of dissemination than women. African Americans and Filipinos have higher rates of dissemination than people of other racial and ethnic groups. We do not know why these groups are at higher risk, but it may be due to genetics.

The immune system is the body’s defense against disease. People with weakened immune systems are also at higher risk of disseminated disease. This includes organ transplant patients, Hodgkin’s disease patients, diabetes patients, pregnant women in their third trimester, people taking corticosteroids (prednisone, dexamethasone, etc.), certain types of drugs for autoimmune diseases, or chemotherapy, and HIV/AIDS patients.

How is Valley Fever diagnosed?

Valley Fever can be confused with many other diseases including cancer and tuberculosis. A blood test is the best way to diagnose the disease. The blood test (also called serology) measures antibodies to the fungus. A negative test does not rule out Valley Fever because it can take time for the body to develop antibodies. Repeated tests are often required. Tissue biopsies, body fluid, and sputum can also be tested for the fungus. X-rays are used to follow the progress of the disease.

What is the treatment for Valley Fever?

Most of people with Valley Fever recover without treatment. Experts are unsure whether antifungal treatment speeds up recovery or prevents complications. Talk to your doctor about whether you need treatment. This is particularly important because antifungals can cause side effects. Doctors usually monitor the progress of a patient by chest x-rays, following the cocci serology (blood test) titer and the severity and duration of symptoms. This may require frequent visits to the doctor. If weight loss and night sweats continue, infiltrates in the lungs enlarge, and the patient us unable to perform daily functions, treatment with antifungal medication usually is considered. In rare cases, surgery may be required. Antibiotics have no effect on the fungus and should be avoided unless prescribed by a doctor.

What are the medications used to treat Valley Fever? What are the side effects?

If your doctor determines that you need treatment for Valley Fever, he or she may prescribe antifungal medication. Valley Fever is not treated with antibiotics because it is caused by a fungus, not bacteria. The most commonly used drug to treat Valley Fever is fluconazole, also known as Diflucan®. Other drugs used to treat Valley Fever include ketoconzale, itraconazole, posaconazole, and voriconazole. These are generally taken by mouth in pill form. In serious cases, Amphotericin B is used. This is either injected into the blood or in the case of brain infections, directly into the fluid around the brain. The length of treatment can vary from a few months to lifelong therapy for severe cases.

All antifungal medications can cause side effects. Depending upon the drug, these can include hair loss, nausea, vomiting, rash, diarrhea, and abdominal pain. Amphotericin B can damage the kidneys and requires close monitoring. Talk to your doctor or pharmacist for more information.

How do I find a doctor?

Any primary care provider should be able to diagnose and treat Valley Fever. If you don’t have health insurance, visit your local community health center. If you would like to find a Valley Fever specialist and you live in Arizona, visit the Valley Fever Center for Excellence to request information. You may also seek care at the Valley Fever Center at St. Joseph’s Hospital in Phoenix. To contact the clinic, call 602-406-8253 or e-mail If you live outside of Arizona, please visit the America Medical Association’s Doctor Finder and search for an infectious disease specialist in your area.

I had Valley Fever in the past. Can I get it again?

Usually lifetime immunity is acquired after an infection which means you will not get it again. Sometime, however, changes in a person's immune system brought about by other diseases or treatments which lower or suppress the immune system can allow the disease to come back or allow a person to be infected again.

How does Valley Fever affect seniors?

Seniors are not more likely to get Valley Fever. However, the immune system becomes weaker with age and the body's ability to fight infections decreases. Older people are also more likely to have other health issues such as diabetes or heart disease and take medication that weakens the immune system. Talk to your doctor about Valley Fever and ask to be tested if you think you have it. If you have Valley Fever, go to your doctor if your symptoms get worse or if you develop new symptoms.

How does Valley Fever affect children?

Children are not more likely to get Valley Fever and do not appear to be at higher risk of developing severe disease than adults. However, they can still become very sick and require treatment, hospitalization, and in rare cases, surgery.

What is being done about Valley Fever?

The Arizona Department of Health Services and the Centers for Disease Control and Prevention are investigating how people are impacted by Valley Fever and educating healthcare providers and the public about the disease. The Valley Fever Center for Excellence (VFCE) at the University of Arizona promotes research, education, and improved patient care for Valley Fever. The VFCE is investigating a new potential drug for Valley Fever called nikkomycin Z. Scientific researchers around the country are working to develop a Valley Fever vaccine, which will take many years.

What can I do to prevent Valley Fever?

There is no way to prevent Valley Fever at this time. Anyone in the areas where the fungus lives can breathe in infectious spores. Avoiding activities associated with dust and airborne dirt of native desert soil is recommended, but it is not guaranteed to prevent infection. Masks may be worn when engaging in some activities or occupations. Use common sense and stay out of the blowing dust. Learn about the disease and tell your friends and family. If you are experiencing symptoms of Valley Fever, ask your doctor to test you for it.

Adapted from the Valley Fever Center for Excellence website FAQ.