Coccidioidomycosis is an endemic systemic mycosis resulting in both asymptomatic and life-threatening disseminated infections.


  • Coccidioides spp. are dimorphic fungi that live in the soil.
  • Endemic to the southwestern United States (southern California, Arizona, western and southern Texas, New Mexico), northern Mexico, and parts of South and Central America
  • Infection is acquired from exposure to aerosolized spores (arthroconidia) usually during recreational or occupational activities; clusters of cases may involve dust storms and earthquakes.
  • The average incubation period is 10 to 16 days (range 1 to 4 weeks) for primary infection.
  • There is no person-to-person spread except in rare instances of draining lesions or donor derived transmission through organ donation.
  • 60% of acute infections are subclinical (asymptomatic).


  • Rising incidence reported in the United States over the past 2 decades
  • Annual incidence in 2011 was 42.6 per 100,000 population.
  • Highest rate of infection in the summer and early fall


Seropositivity rates in children living in endemic area for 1 year approach 20%, whereas rates in children living in endemic area for 10 or more years approach 80%.

Risk Factors

  • The course of illness is highly variable and depend on host immune response and amount of exposure.
  • Risk factors for disseminated infection:
    • Immunosuppression (especially organ transplant recipients, those receiving immunosuppressive therapies and immunomodulators, and those with HIV infection)
    • Male gender (adult)
    • Neonates, infants, and the elderly
    • Filipino, African American, Native American, Hispanic ethnicity
    • Pregnancy
  • Risk of dissemination is less in children than in adults.

General Prevention

  • No special isolation or precautions for the hospitalized patient
  • Contaminated dressings from skin lesions should be handled and discarded with care.
  • Inhalation of aerosolized spores from culture can be hazardous to laboratory personnel.
  • Preventive efforts are aimed at dust control and trials to eliminate organisms from soil.
  • Immunocompromised people should be counseled to avoid activities that may expose them to aerosolized spores in endemic areas.


  • Spores (arthroconidia) are the infectious forms of Coccidioides organisms; they are released from the mold and propagate the mold in the soil.
  • Inhalation of arthroconidia from disturbed, arid soil is the major route of infection.
  • In tissues, arthroconidia enlarge to form spherules. Mature spherules release endospores that propagate in the host and continue the tissue cycle.
  • Primary infection occurs in the lungs.
  • Most patients have infection limited to a localized area of lung and hilar lymph nodes after mounting an intense inflammatory response with granuloma formation.
  • Extrapulmonary dissemination occurs via lymphatic or hematologic spread and usually involves the skin, bones and joints, and central nervous system but can spread to virtually any organ system.


  • Coccidioides immitis and Coccidioides posadasii are the etiologic agents of coccidioidomycosis.
  • Asymptomatic infection is the most common outcome, occurring in 60% of infected individuals.
  • Primary pulmonary infection accounts for most symptomatic cases; nonspecific illness most common feature (cough, malaise, chest pain, fever); self-limited in most cases; may be accompanied by reactive rashes such as erythema multiforme or erythema nodosum
  • Disseminated disease occurs in <1% of infected individuals and may manifest with
    • Osteomyelitis:
      • Subacute or chronic and frequently involves more than one bone (40%)
      • Common sites are the hands, feet, ribs, skull, and vertebrae.
    • Meningitis:
      • Develops within 6 months of initial infection
      • Hydrocephalus is a common complication.
      • Central nervous system vasculitis and intracerebral abscesses are rare.
    • Cutaneous disease:
      • Papules or pustular lesions that ulcerate are most common.
      • Most commonly seen on the face but can occur anywhere
      • Regional adenitis is common.

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