Valley fever

DEFINITION

Valley fever is a fungal infection caused by coccidioides (kok-sid-e-OY-deze) organisms. It can cause fever, chest pain and coughing, among other signs and symptoms.

Two species of coccidioides fungi cause valley fever. These fungi are commonly found in soil in specific regions. The fungi’s spores can be stirred into the air by anything that disrupts the soil, such as farming, construction and wind.

The fungi can then be breathed into the lungs and cause valley fever, also known as acute coccidioidomycosis (kok-sid-e-oy-doh-my-KOH-sis). Mild cases of valley fever usually resolve on their own. In more severe cases, doctors prescribe antifungal medications that can treat the underlying infection.

CAUSES

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.

SYMPTOMS

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

When to see a doctor

Seek medical care if you are over 60, have a weakened immune system, are pregnant, or are black or Filipino, and you develop the signs and symptoms of valley fever, especially if you:

• Live in or have recently traveled to an area where this disease is common
• Have symptoms that aren’t improving
• Be sure to tell your doctor if you’ve traveled to a place where valley fever is endemic and you have symptoms.