Valley fever is the initial form of coccidioidomycosis infection. This initial, acute illness can develop into a more serious disease, including chronic and disseminated coccidioidomycosis.

Acute coccidioidomycosis (valley fever)

The initial, or acute, form of coccidioidomycosis is often mild, with few, if any, symptoms. When signs and symptoms do occur, they appear one to three weeks after exposure. They tend to resemble those of the flu, and can range from minor to severe, including:

• Fever
• Cough
• Chest pain
• Chills
• Night sweats
• Headache
• Fatigue
• Joint aches
• Red, spotty rash

The rash that sometimes accompanies valley fever is made up of painful red bumps that may later turn brown. The rash mainly appears on your lower legs, but sometimes on your chest, arms and back. Others may have a raised red rash with blisters or eruptions that look like pimples.

If you don't become ill from valley fever, you may only find out you've been infected when you later have a positive skin or blood test or when small areas of residual infection (nodules) in the lungs show up on a routine chest X-ray. Although the nodules typically don't cause problems, they can look like cancer on X-rays.

If you do develop symptoms, especially severe ones, the course of the disease is highly variable. It can take months to fully recover, and fatigue and joint aches can last even longer. The severity of the disease depends on several factors, including your overall health and the number of fungus spores you inhale.

Chronic coccidioidomycosis

If the initial coccidioidomycosis infection doesn't completely resolve, it may progress to a chronic form of pneumonia. This complication is most common in people with weakened immune systems.

Signs and symptoms include:

• Low-grade fever
• Weight loss
• Cough
• Chest pain
• Blood-tinged sputum (matter discharged during coughing)
• Nodules in the lungs

Disseminated coccidioidomycosis

The most serious form of the disease, disseminated coccidioidomycosis, occurs when the infection spreads (disseminates) beyond the lungs to other parts of the body. Most often these parts include the skin, bones, liver, brain, heart, and the membranes that protect the brain and spinal cord (meninges).

The signs and symptoms of disseminated disease depend on which parts of your body are affected and may include:

• Nodules, ulcers and skin lesions that are more serious than the rash that sometimes occurs with other forms of the disease
• Painful lesions in the skull, spine or other bones
• Painful, swollen joints, especially in the knees or ankles
• Meningitis — an infection of the membranes and fluid surrounding the brain and spinal cord

The fungi that cause valley fever — Coccidioides immitis or Coccidioides posadasii — thrive in the arid desert soils of southern Arizona, Nevada, northern Mexico and California's San Joaquin Valley. They're also endemic to New Mexico, Texas, and parts of Central and South America — areas with mild winters and arid summers.

Like many other fungi, coccidioides species have a complex life cycle. In the soil, they grow as a mold with long filaments that break off into airborne spores when the soil is disturbed.

The spores are extremely small and can be carried hundreds of miles by the wind. Once inside the lungs, the spores reproduce, perpetuating the cycle of the disease.

• Environmental exposure. Anyone who inhales the spores that cause valley fever is at risk of infection. People who have jobs that expose them to dust are most at risk — construction, road and agricultural workers, ranchers, archeologists, and military personnel on field exercises.
• Race. For reasons that aren't well-understood, people of Filipino and African heritage are more susceptible to developing serious infection with coccidioidomycosis.
• Pregnancy. Pregnant women are vulnerable to more serious coccidioidomycosis during the third trimester, and new mothers are vulnerable right after their babies are born.
• Weakened immune system. Anyone with a weakened immune system is at increased risk of serious complications. This includes people living with AIDS or those being treated with steroids, chemotherapy and anti-rejection drugs after transplant surgery. People with certain autoimmune diseases, such as rheumatoid arthritis or Crohn's disease, who are being treated with anti-tumor necrosis factor (TNF) drugs also have an increased risk of infection.
• Age. Older adults are more likely to develop valley fever. This may be because their immune systems are less robust or because they have other medical conditions that affect their overall health.

Some people, especially pregnant women, people with weakened immune systems — such as those living with HIV/AIDS — and those of Filipino or African heritage are at risk of developing a more severe form of coccidioidomycosis.

Complications of coccidioidomycosis may include:

• Severe pneumonia. Most people recover from coccidioidomycosis-related pneumonia without complications. Others, mainly people of Filipino and African heritage, and those with weakened immune systems, may become seriously ill.
• Ruptured lung nodules. A small percentage of people develop thin-walled nodules (cavities) in their lungs. Many of these eventually disappear without causing any problems, but some may rupture, causing chest pain and difficulty breathing. A ruptured lung nodule might require the placement of a tube into the space around the lungs to remove the air or surgery to repair the damage.
• Disseminated disease. This is the most serious complication of coccidioidomycosis. If the fungus spreads (disseminates) throughout the body, it can cause problems ranging from skin ulcers and abscesses to bone lesions, severe joint pain, heart inflammation, urinary tract problems and meningitis — a potentially fatal infection of the membranes and fluid covering the brain and spinal cord.