Updated: May 27, 2008
Coccidioides immitis, the etiologic agent responsible for coccidioidomycosis and the more well-known San Joaquin Valley Fever, is a dimorphic fungus. It has a mold and a yeast form and is endemic to the Southwestern United States and other lower Sonoran climates of Central America and South America. It was first described in the late 1800s; however, most cases at that time were consistent with more severe cases of C immitis infection, and many of the more benign cases were not recognized until 1929, with an unintentional exposure of a medical student at Stanford University. The medical student subsequently developed a respiratory tract infection and lived, sparking interest that resulted in the eventual connection between C immitis and San Joaquin Valley Fever.
C immitis infections occur when inhaled arthroconidia (spores) are deposited in the lower airways and subsequently change morphology to a spherule. These spherules enlarge, divide, and rupture, releasing hundreds of 2-5 micron spherule particles, which similarly reproduce. During primary infection, a mononuclear infiltrate may develop followed by subsequent conversion to polymorphonuclear predominance.
Th1-helper cells are important in the development of effective immunity. Observational data and experimental models show that lack of Th1 cells or predominance of Th2 cells results in higher rates of disseminated disease (eg, human immunodeficiency virus [HIV], acquired immunodeficiency syndrome [AIDS], certain lymphomas, posttransplant states, chronic steroid dependence).1 C immitis infection can also occur by direct inoculation (eg, from contaminated penetrating objects).
Other rare case reports have been documented, such an infected lung transplant case and sexually transmitted cases. Some of the phagocytized arthroconidia are theorized to be transported back to draining lymph nodes by macrophages and can cause lymphangitis. The inoculating dose responsible for infection is small and may be 10 or less arthroconidia.
C immitis infection rates are typically quoted in the 100,000 per year range within the United States. Peak incidence occurs during the summer to early fall months and is related to the variations in weather and spore formation. In particular, outbreaks have been documented during earthquakes and wind storms, which agitate arthroconidia and cause them to become airborne.
Historically, people at greatest risk for contact include farmers, construction workers, and archaeologists; the Northridge earthquake and outbreaks among archaeologists highlight these events.2,3 Thus, otherwise healthy persons exposed to high spore burdens have a higher likelihood of more severe disease. C immitis cases are by no means confined to the Southwestern United States; in fact, cases have been reported in travelers who visited endemic areas. This illustrates the need for careful history taking and possible exposure in endemic areas.
Affected areas include the lower Sonoran areas, which are characterized by semiarid climates with hot summers and alkaline soil. These areas include northern Mexico, Central America, and South America.
C immitis infection is rarely fatal, except in those who may be extremely immunocompromised. Residual pulmonary disease occurs in 5-10% of patients, and only about 1% of patients progress to disseminated disease.
Any person with impaired cellular immunity has a greater risk for disseminated disease. Individuals with HIV or AIDS are particularly susceptible to more severe disease, especially those with CD4 counts of less than 250. The risk of dissemination is also increased during pregnancy; the risk is slightly higher with each progressive trimester. Patients with lymphoma, those who have undergone solid organ transplant, and patients receiving long-term corticosteroid treatment also have a higher risk of dissemination. Recent advances in immunosuppressive therapy with tumor necrosis factor (TNF)-alpha inhibitors have also been proposed as a risk factor for advanced or disseminated disease.4
Filipinos, blacks, and Hispanics have an increased risk of disseminated disease compared with whites.5 Studies have shown that genotypic variations in human leukocyte antigen (HLA) either confer increased risk or reduced risk of dissemination. Hispanics with A or B type blood groups also have a slightly higher risk for advanced and/or disseminated disease compared with the population as a whole.6
Low income has been associated with a predisposition for severe pulmonary infection and disseminated disease. The role of health care access in this observation is unknown.
Incidence is equal in males and females.
All age groups can be affected. Congenital infection is rarely a factor in childhood coccidioidomycosis. In disseminated disease, the mortality rates in neonates and infants are much higher than those seen in children, adolescents, and adults.
The natural history of C immitis infection is usually one of a self-limited respiratory tract infection, which occurs 1-3 weeks after exposure. Most cases (60%) are subclinical and never reach the attention of a physician.
Common symptoms are nonspecific and include fever, cough, chest pain, fatigue, dyspnea, headache, arthralgias, and/or myalgias. Skin manifestations are also seen in a small percentage of cases. In addition to the above symptoms, infection can progress to various presentations. The triad of fever, erythema nodosum, and arthralgias is commonly referred to as San Joaquin Valley Fever or desert rheumatism.
Primary pulmonary infection may progress to overt pneumonia, chronic lung infections, hematogenous spread, disseminated disease, and meningitis. Clinical suspicion and eliciting a history of possible exposure or travel to an endemic area are important.
Coccidioidomycosis is caused by C immitis, a soil fungus particularly adapted to arid conditions.
| Babesiosis | Pneumonia, Empyema and Abscess |
| Erythema Multiforme | Pneumonia, Immunocompromised |
| Granuloma, Annulare and Pyogenic | Pneumonia, Mycoplasma |
| Meningitis | Pneumonia, Viral |
| Neoplasms, Lung | Sarcoidosis |
| Pleural Effusion | Tuberculosis |
| Pneumonia, Aspiration | |
| Pneumonia, Bacterial |
Histoplasmosis
Blastomycosis
Paracoccidioidomycosis
Other fungi
Lung abscess
Lymphoma
Other causes of cough, fever, and fatigue
Old granuloma
Guide diagnostic evaluation by index of suspicion and patient's clinical presentation. Various tests may aid or confirm the diagnosis.
If unable to obtain a diagnosis by skin testing or serology, consider performing the following:
In general, the severity and tempo of the disease usually dictates tempo of treatment. In patients with suspected or documented uncomplicated primary infection, treatment varies from careful observation to long-term azole therapy.
Some authors have suggested that empiric treatment may decrease the rate of disseminated infection, but this has not been proven in any controlled studies and no conclusive guidelines specify which uncomplicated infections need treatment. However, groups who are at risk for dissemination (eg, blacks, Filipinos, individuals with HIV or AIDS, individuals with diabetes mellitus, women in the third trimester of pregnancy) warrant more aggressive treatment. Typically, this may be accomplished with fluconazole except in pregnant women because azole antifungals are teratogenic. Pregnant women with suspected infection may be treated with amphotericin B. Currently, few randomized controlled trials have specifically looked at the efficacy of the different azoles. Galgiani et al compared fluconazole with itraconazole in a randomized controlled trial.7 Although no statistically significant difference was noted, itraconazole was associated with better outcomes in musculoskeletal disease.
Patients with more advanced disease require more aggressive treatment. In particular, patients who exhibit signs of meningitis need either intravenous antibiotic therapy with amphotericin unless otherwise contraindicated or high-dose azole therapy with or without intrathecal amphotericin. Some case reports have suggested that voriconazole or posaconazole may be therapeutic options in these patients;8,9 however, these reports are only anecdotal to date, and no comparative studies have been performed. Caspofungin in combination with fluconazole has been cited as beneficial in a case report of a 31-year-old Korean man with coccidioidal pneumonia.10 Steroids may be somewhat beneficial in patients with vasculitis.
The mechanism of action in these agents may involve an alteration of RNA and DNA metabolism or an intracellular accumulation of peroxide that is toxic to the fungal cell.
Depending on concentration attained in body fluids and on fungal susceptibility, agent can be fungistatic or fungicidal. This polyene antibiotic produced by strain of Streptomyces nodosus changes membrane permeability by binding to sterols in fungal cell membrane; fungal cell death results.
0.5-1 mg/kg/d IV; not to exceed 2-4 g/dose
2.5 mg/kg/d IV
Antineoplastic agents may enhance potential of amphotericin B for renal toxicity, bronchospasm, and hypotension; corticosteroids, digitalis, and thiazides may potentiate hypokalemia; risk of renal toxicity increased with cyclosporine
Documented hypersensitivity
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Monitor renal function, serum electrolytes such as magnesium and potassium, liver function, CBC count, and hemoglobin concentrations; resume therapy at lowest dose (eg, 0.25 mg/kg) when interrupted for >7 d; hypoxemia, acute dyspnea, and interstitial infiltrates may occur in patients with neutropenia receiving leukocyte transfusions (separate time of amphotericin infusion from time of leukocyte transfusion)
Synthetic bistriazole antifungal agent; highly selective inhibitor of fungal cytochrome P-450 and sterol C-14 alpha-demethylation with broad-spectrum activity.
200-400 mg PO qd
3-6 mg/kg PO qd for 14-28 d depending on severity of infection
Levels may increase with hydrochlorothiazides; levels may decrease with long-term coadministration of rifampin; may decrease phenytoin concentrations; may increase concentrations of theophylline, tolbutamide, glyburide, and glipizide; may increase effects of anticoagulants; may increase cyclosporine concentration
Documented hypersensitivity
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Not recommended for breastfeeding mothers
Monitor closely if rashes develop and discontinue drug if lesions progress; may cause clinical hepatitis, cholestasis and fulminant hepatic failure (including death) with underlying medical conditions such as AIDS or a malignancy and while taking multiple concomitant medications
Imidazole broad-spectrum antifungal agent. Impairs synthesis of ergosterol, allowing increased permeability and leakage of cellular components.
200-400 mg PO qd
Not established
Isoniazid may decrease bioavailability; coadministration with rifampin decreases effects of either drug; may increase effect of anticoagulants; may increase toxicity of corticosteroids and cyclosporine (cyclosporine dosage can be adjusted); may decrease theophylline levels
Documented hypersensitivity; fungal meningitis
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Hepatotoxicity may occur; may reversibly decrease corticosteroid serum levels (adverse effects avoided with dose of 200-400 mg/d)
Testosterone levels are reduced by doses of 800 mg/d and abolished by doses of 1600 mg/d (once therapy discontinued, levels return to baseline values); decreases ACTH-induced corticosteroid serum levels at high doses (to avoid these effects, closely follow recommended dose of 200-400 mg/d)
Requires acidity for dissolution and absorption (if antacids, anticholinergics, or H2-blockers are needed, give >2 h after ketoconazole)
Triazole analogue of ketoconazole
400-600 mg PO qd
Specific dosing in children with coccidioidomycosis not studied; in other antifungal regimen recommend dose is 5 mg/kg/d PO divided qd/bid; max dose 10 mg/kg/d
Antacids may reduce absorption; edema may occur with coadministration of calcium channel blockers (eg, amlodipine, nifedipine); hypoglycemia may occur with sulfonylureas; high doses may increase tacrolimus and cyclosporine plasma concentrations; rhabdomyolysis may occur with coadministration of HMG-CoA reductase inhibitors (lovastatin or simvastatin); coadministration with cisapride can cause cardiac rhythm abnormalities and death; may increase digoxin levels; coadministration may increase plasma levels of midazolam or triazolam; phenytoin and rifampin may reduce levels (phenytoin metabolism may be altered)
Documented or suspected drug allergies or hypersensitivity; CHF or liver dysfunction
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Use cautiously in patients with hepatic insufficiency
Triazole antifungal agent that inhibits fungal cytochrome P450-mediated 14 alpha-lanosterol demethylation, which is essential in fungal ergosterol biosynthesis.
200 mg PO bid or 3-6 mg/kg IV q12h
Not established
CYP450 2C19 (highest affinity), 2C9, and 3A4 (minor) substrate and inhibitor; CYP450 inducers (eg, rifampin) have shown to decrease steady state peak plasma levels by up to 93%; may increase serum levels of drugs metabolized by CYP450 2C19 or 2C9, of which some are contraindicated (eg, sirolimus, pimozide, quinidine, cisapride, ergot alkaloids), others may need more frequent monitoring (eg, cyclosporine, tacrolimus, warfarin, HMG-CoA inhibitors, benzodiazepines, calcium channel blockers)
Documented hypersensitivity; CrCl <50 mL/min (decreased excretion of IV vehicle) if administering IV; coadministration with rifampin, rifabutin, carbamazepine, barbiturates, sirolimus, pimozide, quinidine, cisapride, ergot alkaloids
D - Fetal risk shown in humans; use only if benefits outweigh risk to fetus
Decrease maintenance dose in hepatic dysfunction; common adverse effects include visual disturbances, fever, rash, vomiting, nausea, diarrhea, headache, sepsis, peripheral edema, abdominal pain, rash (including Stevens-Johnson syndrome and phototoxicity), and respiratory disorder; rare cases of severe hepatotoxicity reported; administer PO dosage form 1 h ac or pc
Triazole antifungal agent that possesses structural similarities to itraconazole. Blocks ergosterol synthesis by inhibiting the enzyme lanosterol 14-alpha-demethylase and sterol precursor accumulation. This action results in cell membrane disruption. Available as PO susp (200 mg/5 mL). Indicated for prophylaxis of invasive Aspergillus and Candida infections in patients at high risk because of severe immunosuppression.
200 mg (5 mL) PO tid with food or liquid nutritional supplement to enhance absorption
<13 years: Not established
>13 years: Administer as in adults
Metabolized via UDP glucuronidation; P-gp efflux substrate; CYP3A4 inhibitor
UDP-G inducers (eg, rifabutin, phenytoin) and drugs that increase gastric pH (eg, cimetidine) decrease serum levels (avoid concomitant use unless benefit outweighs risk)
Inhibits CYP3A4 and may elevate serum levels of cyclosporine, tacrolimus, sirolimus, rifabutin, midazolam, phenytoin, calcium channel blockers (eg, nifedipine, bepridil), HMG-CoA reductase inhibitors (eg, lovastatin, pravastatin), ergot alkaloids, terfenadine, astemizole, cisapride, pimozide, halofantrine, quinidine, or vinca alkaloids (eg, vincristine, vinblastine)
Documented hypersensitivity; coadministration with ergot alkaloids; coadministration with CYP3A4 substrates likely to result in serious toxicities (eg, terfenadine, astemizole, cisapride, pimozide, halofantrine, quinidine)
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Common adverse effects include nausea, vomiting, diarrhea, rash, hypokalemia, thrombocytopenia, and elevated liver enzyme levels; closely monitor patients with severe diarrhea or vomiting for breakthrough fungal infections; rare adverse events include arrhythmias caused by QTc prolongation, bilirubinemia, or liver function impairment; caution with preexisting cardiac risk factors (eg, history of arrhythmia, hypokalemia, hypomagnesemia); food improves absorption and provides optimal serum concentration; shake well before use; administer with measuring spoon provided in package; avoid if breastfeeding
First of a new class of antifungal drugs (glucan synthesis inhibitors). Inhibits synthesis of beta-(1,3)-D-glucan, an essential component of fungal cell wall.
Not established; typical antifungal regimens suggest starting at 70 mg IV on day 1 followed by 50 mg IV qd
Not established
Coadministration with cyclosporine may increase risk of hepatotoxicity; carbamazepine, nelfinavir, efavirenz, or dexamethasone may decrease levels of caspofungin; caspofungin may decrease levels of tacrolimus; rifampin decreases caspofungin levels by 30% (ie, adjust dose to 70 mg/d)
Documented or suspected drug allergies or hypersensitivity
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Caution in moderate hepatic dysfunction (ie, decrease dose to 35 mg/d); may exacerbate preexisting renal dysfunction or myelosuppression
Indications for admission include the following:
Ampel NM. Combating opportunistic infections: coccidioidomycosis. Expert Opin Pharmacother. Feb 2004;5(2):255-61. [Medline].
CDC. Coccidioidomycosis following the Northridge earthquake--California, 1994. JAMA. Jun 8 1994;271(22):1735. [Medline].
Schneider E, Hajjeh RA, Spiegel RA, et al. A coccidioidomycosis outbreak following the Northridge, Calif, earthquake. JAMA. Mar 19 1997;277(11):904-8. [Medline].
Bergstrom L, Yocum DE, Ampel NM. Increased risk of coccidioidomycosis in patients treated with tumor necrosis factor alpha antagonists. Arthritis Rheum. Jun 2004;50(6):1959-66. [Medline].
CDC. Increase in coccidioidomycosis--Arizona, 1998-2001. MMWR Morb Mortal Wkly Rep. Feb 14 2003;52(6):109-12. [Medline].
Louie L, Ng S, Hajjeh R, et al. Influence of host genetics on the severity of coccidioidomycosis. Emerg Infect Dis. Sep-Oct 1999;5(5):672-80. [Medline].
Galgiani JN, Catanzaro A, Cloud GA. Comparison of oral fluconazole and itraconazole for progressive, nonmeningeal coccidioidomycosis. A randomized, double-blind trial. Mycoses Study Group. Ann Intern Med. Nov 7 2000;133(9):676-86. [Medline].
Prabhu RM, Bonnell M, Currier BL. Successful treatment of disseminated nonmeningeal coccidioidomycosis with voriconazole. Clin Infect Dis. Oct 1 2004;39(7):e74-7. [Medline].
Anstead GM, Corcoran G, Lewis J. Refractory coccidioidomycosis treated with posaconazole. Clin Infect Dis. Jun 15 2005;40(12):1770-6. [Medline].
Park DW, Sohn JW, Cheong HJ. Combination therapy of disseminated coccidioidomycosis with caspofungin and fluconazole. BMC Infect Dis. 2006;6:26. [Medline].
Deresinski S. Coccidioides immitis as a potential bioweapon. Semin Respir Infect. Sep 2003;18(3):216-9. [Medline].
Blair JE, Smilack JD, Caples SM. Coccidioidomycosis in patients with hematologic malignancies. Arch Intern Med. Jan 10 2005;165(1):113-7. [Medline].
Catanzaro A. Coccidioidomycosis. In: Manual of Clinical Problems in Pulmonary Medicine. 5th ed. Lippincott Williams & Wilkins; 2000.
Comrie AC. Climate factors influencing coccidioidomycosis seasonality and outbreaks. Environ Health Perspect. Jun 2005;113(6):688-92. [Medline].
Deresinski SC, Mirels LF, Kemper CA. Coccidioides immitis. In: Infectious Diseases. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:2227-46.
Galgiani J. Coccidioides immitis. In: Principles and Practice of Infectious Diseases. New York, NY: Churchill Livingstone; 2000:2746-57.
Jones JL, Fleming PL, Ciesielski CA, et al. Coccidioidomycosis among persons with AIDS in the United States. J Infect Dis. Apr 1995;171(4):961-6. [Medline].
Rosenstein NE, Emery KW, Werner SB. Risk factors for severe pulmonary and disseminated coccidioidomycosis: Kern County, California, 1995-1996. Clin Infect Dis. Mar 1 2001;32(5):708-15. [Medline].
coccidioidomycosis, desert fever, Posadas-Wernicke disease, San Joaquin fever, San Joaquin Valley Fever, cocci fungal infection, Coccidioides immitis, CI, arthroconidia, extrapulmonary coccidioidomycosis disease, human immunodeficiency virus, HIV, acquired immunodeficiency syndrome, AIDS, certain lymphomas, posttransplant states, chronic steroid dependence, severe pulmonary infection, erythema nodosum, desert rheumatism, pneumonia, hemoptysis, pneumothorax, noncommunicating hydrocephalus, increased intracranial pressure, pericardial effusion, tamponade, osteomyelitis, septic arthritis, synovitis
James de la Torre, MD, Staff Physician, Resident Emergency Medicine, Department of Emergency Medicine, University of Southern California/Los Angeles County Medical Center
Disclosure: Nothing to disclose.
Allison J Richard, MD, Instructor of Clinical Emergency Medicine, Keck School of Medicine, University of Southern California; Consulting Staff, Department of Emergency Medicine, LAC-USC Medical Center
Allison J Richard, MD is a member of the following medical societies: International Society of Travel Medicine
Disclosure: Nothing to disclose.
Joseph Kim, MD, Chairman, Department of Emergency Medicine, Western Medical Center; Clinical Instructor, University of California at Irvine
Disclosure: Nothing to disclose.
David FM Brown, MD, Assistant Professor, Department of Medicine, Division of Emergency Medicine, Harvard Medical School; Associate-Chief, Attending Physician, Department of Emergency Medicine, Massachusetts General Hospital
David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.
Barry J Sheridan, DO, Chief, Department of Emergency Medical Services, Brooke Army Medical Center
Barry J Sheridan, DO is a member of the following medical societies: American Academy of Emergency Medicine
Disclosure: Nothing to disclose.
John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
Barry E Brenner, MD, PhD, FACEP, Program Director, Department of Emergency Medicine, University Hospitals, Case Medical Center
Barry E Brenner, MD, PhD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Chest Physicians, American College of Emergency Physicians, American College of Physicians, American Heart Association, American Thoracic Society, Arkansas Medical Society, New York Academy of Medicine, New York Academy of Sciences, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.
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