Could This Illness be Coccidioidomycosis?

New guidelines provide expanded diagnostic and treatment information on this often underdiagnosed condition.

The Infectious Diseases Society of America (IDSA) has updated guidelines for the management of coccidioidomycosis  (valley fever) for the first time in more than 10 years.1

Coccidioides species, dimorphic fungi found in desert soils across the southwestern United States and Mexico, cause infection when airborne arthroconidia are inhaled. A small percentage of cases result in severe pulmonary manifestations or extrapulmonary complications.

Immunocompromising conditions, including pregnancy, increase the risk of severe illness. Infectious disease consultants typically see the more severe end of the disease spectrum. However, the vast majority of infections are mild and resolve without treatment.

The new IDSA guidelines contain greatly expanded information on the management of complications of coccidioidomycosis that will be valuable for specialists. They also include new sections addressing the clinical spectrum, diagnosis, and management of early infection. Infected patients may present to health care providers with a nonspecific syndrome of respiratory, skin, or joint symptoms for which the differential diagnosis is broad.

“Valley fever is underdiagnosed in part because past guidelines were directed to the specialists, whereas most of these patients initially see their primary care physicians, many of whom aren’t aware just how common this infection is,” John N. Galgiani, MD, lead author of the guidelines noted in a prepared statement.2 “About a third of cases of pneumonia in Arizona are caused by valley fever. Doctors need to ask patients with pneumonia about their travel history and if they’ve recently traveled to endemic areas, and need to consider valley fever.”

In endemic areas, coccidioidomycosis may be the most common diagnosable cause of community-acquired pneumonia. Nevertheless, early, mild infection frequently goes undiagnosed. Because of the increasing mobility of the US population, cases may also present in nonendemic areas where health care providers often have very low awareness of coccidioidomycosis. 

Coccidioidomycosis may be diagnosed in patients with possible exposure in the past 1 to 2 months and a compatible syndrome by testing for serum antibodies using simple and widely available enzyme immunoassays.

Fungal culture of suitable specimens also improves diagnostic yield. As discussed in the guidelines, correctly diagnosing these cases, which generally do not require antifungal therapy, is important to avoid unnecessary diagnostic testing and prescription of ineffective antimicrobial agents, to educate patients, and to manage and monitor convalescence.

The guidelines continue to recommend oral azole antifungal agents, usually fluconazole, as the preferred treatment for most manifestations of coccidioidomycosis that require treatment, including infection in the second and third trimesters of pregnancy. Amphotericin remains recommended in the first trimester. High-dose azoles, certain newer azoles, or amphotericin are recommended treatment options when first-line therapy fails.


1.  Galgiani JN, Ampel NM, Blair JE, et al. 2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the treatment of coccidioidomycosis. Clin Infect Dis. 2016; doi:10.1093/cid/ciw360.

2. Infectious Diseases Society of America. Valley Fever diagnosis often missed [press release].  Arlington, VA; Infectious Diseases Society of America: July 28, 2016.