The term "South American blastomycosis" is sometimes used to describe infection with Paracoccidioides brasiliensis,[1] though the term Paracoccidioidomycosis is more frequently used to describe this condition.
Classification and external resources

Blastomyces dermatitidis, the causative agent of blastomycosis.
ICD-10 B40
ICD-9 116.0
DiseasesDB 1439
MedlinePlus 000102
eMedicine med/231 ped/254
MeSH D001759

Blastomycosis (also known as "North American blastomycosis," "Blastomycetic dermatitis," and "Gilchrist's disease"[2]:319) is a fungal infection caused by the organism Blastomyces dermatitidis. Endemic to portions of North America, blastomycosis causes clinical symptoms similar to histoplasmosis.[3]


Signs and symptoms

Blastomycosis of skin

Blastomycosis can present in one of the following ways:

  • a flu-like illness with fever, chills, myalgia, headache, and a nonproductive cough which resolves within days.
  • an acute illness resembling bacterial pneumonia, with symptoms of high fever, chills, a productive cough, and pleuritic chest pain.
  • a chronic illness that mimics tuberculosis or lung cancer, with symptoms of low-grade fever, a productive cough, night sweats, and weight loss.
  • a fast, progressive, and severe disease that manifests as ARDS, with fever, shortness of breath, tachypnea, hypoxemia, and diffuse pulmonary infiltrates.
  • skin lesions, usually asymptomatic, appear as ulcerated lesions with small pustules at the margins
  • bone lytic lesions can cause bone or joint pain.
  • prostatitis may be asymptomatic or may cause pain on urinating.
  • laryngeal involvement causes hoarseness.


Infection occurs by inhalation of the fungus from its natural soil habitat. Once inhaled in the lungs, they multiply and may disseminate through the blood and lymphatics to other organs, including the skin, bone, genitourinary tract, and brain. The incubation period is 30 to 100 days, although infection can be asymptomatic.


Once suspected, the diagnosis of blastomycosis can usually be confirmed by demonstration of the characteristic broad based budding organisms[4] in sputum or tissues by KOH prep, cytology, or histology. Tissue biopsy of skin or other organs may be required in order to diagnose extra-pulmonary disease. Commercially available urine antigen testing appears to be quite sensitive in suggesting the diagnosis in cases where the organism is not readily detected. While culture of the organism remains the definitive diagnostic standard, its slow growing nature can lead to delays in treatment of up to several weeks.

However, sometimes blood and sputum cultures may not detect blastomycosis; lung biopsy is another option, and results will be shown promptly.


Itraconazole given orally is the treatment of choice for most forms of the disease. Ketoconazole may also be used. Cure rates are high, and the treatment over a period of months is usually well tolerated. Amphotericin B is considerably more toxic, and is usually reserved for immunocompromised patients who are critically ill and those with central nervous system disease. Fluconazole has also been tested on patients in Canada.


Mortality rate in treated cases

  • 0-2% in treated cases among immunocompetent patients
  • 29% in immunocompromised patients
  • 40% in the subgroup of patients with AIDS
  • 68% in patients presenting as acute respiratory distress syndrome (ARDS)


In the United States, blastomycosis is endemic in the Mississippi river and Ohio river basins and around the Great Lakes. The annual incidence is less than 1 case per 100,000 people in Mississippi, Louisiana, Kentucky, and Arkansas. The cases are greater in northern states such as Wisconsin, where from 1986 to 1995 there were 1.4 cases per 100,000 people.[5] It also frequently affects hunting dogs in northern Wisconsin and the upper Mississippi and Wisconsin Rivers.[6]

In Canada, most cases of blastomycosis occur in Northwestern Ontario, particularly around the Kenora area. The moist, acidic soil in the surrounding woodland harbors the fungus.

Blastomycosis is distributed internationally; cases are sometimes reported from Africa.[7]


Blastomycosis was first described by Thomas Casper Gilchrist[8] in 1894 and sometimes goes by the eponym Gilchrist's disease.[9] It is also sometimes referred to as Chicago Disease.

See also


  1. ^ "South American Blastomycosis: Overview - eMedicine Dermatology". Retrieved 2009-03-08. 
  2. ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0. 
  3. ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 676–8. ISBN 0838585299. 
  4. ^ Veligandla SR, Hinrichs SH, Rupp ME, Lien EA, Neff JR, Iwen PC (October 2002). "Delayed diagnosis of osseous blastomycosis in two patients following environmental exposure in nonendemic areas". Am. J. Clin. Pathol. 118 (4): 536–41. doi:10.1309/JEJ0-3N98-C3G8-21DE. PMID 12375640. 
  5. ^ Centers for Disease Control and Prevention (CDC) (1996). "Blastomycosis--Wisconsin, 1986-1995". MMWR Morb. Mortal. Wkly. Rep. 45 (28): 601–3. PMID 8676851. 
  6. ^ Pet Center Blasto in Dogs
  7. ^ Alvarez G, Burns B, Desjardins M, Salahudeen S, AlRashidi F, Cameron D (2006). "Blastomycosis in a young African man presenting with a pleural effusion". Can Respir J 13 (8): 441–4. PMC 2683332. PMID 17149463. 
  8. ^ "Thomas Caspar Gilchrist (". Retrieved 2008-12-10. 
  9. ^ "Gilchrist's disease (". Retrieved 2008-12-10. 

External links

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Look at other dictionaries:

  • blastomycosis — lastomycosis n. any of several fungal infections caused by blastomycetes; they are characterized by inflammatory lesions of skin and mucous membranes or internal organs. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • blastomycosis — [blas΄tōmī kō′sis, blas΄təmī kō′sis] n. [ BLASTO + MYCOSIS] any disease caused by a blastomycete …   English World dictionary

  • blastomycosis — A chronic granulomatous and suppurative disease caused by Blastomyces dermatitidis; originates as a respiratory infection and disseminates, usually with pulmonary, osseous, and/or cutaneous involvement predominating. Formerly called North… …   Medical dictionary

  • blastomycosis — blastomycotic /blas toh muy kot ik/, adj. /blas toh muy koh sis/, n. Pathol. any of several diseases caused by certain yeastlike fungi, esp. blastomycetes. [1895 1900; < NL; see BLASTO , MYCOSIS] * * * ▪ disease       infection of the skin and… …   Universalium

  • blastomycosis — n. any disease caused by parasitic fungi of the genus Blastomyces, which may affect the skin (forming wartlike ulcers and tumours on the face, neck, hands, arms, feet, and legs) or involve various internal tissues, such as the lungs, bones, liver …   The new mediacal dictionary

  • blastomycosis — noun Etymology: New Latin, from Blastomyces, fungus genus, from blast + Greek mykēs fungus; akin to Greek myxa mucus more at mucus Date: circa 1900 any of several fungal infections; especially an infectious disease caused by a yeast fungus… …   New Collegiate Dictionary

  • blastomycosis — (blas to mi ko sis) A systemic fungal infection caused by Blastomyces dermatitidis and marked by suppurating tumors in the skin or by lesions in the lungs …   Dictionary of microbiology

  • blastomycosis — noun A fungal infection caused by the organism Blastomyces dermatitidis, endemic to parts of North America, whose clinical symptoms resemble those of histoplasmosis …   Wiktionary

  • blastomycosis — n. infection of the skin or mucous membrane caused by a blastomycete (parasitic fungus) …   English contemporary dictionary

  • blastomycosis — [ˌblastə(ʊ)mʌɪ kəʊsɪs] noun Medicine a disease of the skin or internal organs caused by infection with parasitic fungi. Origin from mod. L. genus name Blastomyces …   English new terms dictionary

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