South American Blastomycosis
- Author: Julie E Dixon, MD, FAAD; Chief Editor: Dirk M Elston, MD more...
Background
South American blastomycosis is a serious, systemic mycotic infection caused by the thermally dimorphic fungus Paracoccidioides brasiliensis. The fungus is endemic to countries in Central America and South America, most notably Brazil, Argentina, Colombia, and Venezuela, in regions classified as subtropical mountain forests. Infection with P brasiliensis is usually subclinical; however, the fungus sometimes proliferates, causing severe disease.[1]
Two general forms of the disease exist: the subacute juvenile form and the chronic adult form. The chronic adult form accounts for more than 90% of cases. The lungs, skin, mucous membranes, and lymph nodes most frequently are involved. Other internal organs sometimes are affected. Also see Blastomycosis (pediatrics) and Blastomycosis (pulmonology).
Pathophysiology
P brasiliensis is a thermally dimorphic fungus that grows as a mycelium in nature and as yeastlike cells in tissue. Although P brasiliensis has been cultured from the soil, its natural habitat is not well understood. The disease is believed to be initially acquired through the inhalation of the fungus, as with other dimorphic fungi. After the inhalation of conidia, the fungus transforms into yeast cells within the alveolar macrophages. In most patients who are immunocompetent, infection is subclinical, and fungal growth is halted. However, in some patients, after an incubation period of weeks to decades, the fungus reactivates and disseminates, causing granulomatous disease in multiple tissues.[2] Most commonly, the lungs are affected, followed by the mucous membranes, skin, lymph nodes, and various internal organs.
Epidemiology
Frequency
United States
The fungus is not endemic to the United States. A number of cases have been reported in patients who previously visited or resided in endemic areas.[3]
International
South American blastomycosis is restricted to Central America and South America, with about 80% of cases occurring in Brazil. About 6-50% of people living in endemic regions have positive paracoccidioidin skin test results, which indicate prior infection. Antibodies to P brasiliensis have been detected in 27% of blood donors in Brazil.[4, 5, 6, 7] Of the 90 million people living in endemic areas, approximately 10 million are infected, although exact figures are difficult to obtain.[8]
Mortality/Morbidity
- The mortality rate is high for both the chronic adult and subacute juvenile forms if untreated. With treatment, the mortality rate is 7-10% for children and 1-10% for adults.[9]
- In patients with HIV, the mortality rate is 30-45%.
- Complications generally result from fibrotic scarring that occurs during healing. Patients can have residual chronic lung, oral, nasal, pharyngeal, and laryngeal problems after the lungs or mucous membranes heal. If internal organs, such as the adrenal glands, are affected, chronic organ dysfunction (ie, Addison disease) can develop.
Sex
- The chronic adult form affects men more frequently than women, with a ratio of about 15:1. The fungus has receptors that bind estrogen. Binding of estrogen prevents the transformation of the mycelium into the yeast phase, which is necessary for tissue invasion. This inhibition has been hypothesized to explain the extreme sex differences despite the fact that equal numbers of men and women have positive paracoccidioidin skin test results and that equal numbers of prepubertal boys and girls have the subacute juvenile type.
- The subacute juvenile form affects both sexes equally.
Age
- Most patients are adult men aged 30-50 years.
- Children are affected in only 3-5% of cases.
Lupi O, Tyring SK, McGinnis MR. Tropical dermatology: fungal tropical diseases. J Am Acad Dermatol. Dec 2005;53(6):931-51, quiz 952-4. [Medline].
Benard G, Kavakama J, Mendes-Giannini MJ, Kono A, Duarte AJ, Shikanai-Yasuda MA. Contribution to the natural history of paracoccidioidomycosis: identification of the primary pulmonary infection in the severe acute form of the disease--a case report. Clin Infect Dis. Jan 1 2005;40(1):e1-4. [Medline].
Mayr A, Kirchmair M, Rainer J, Rossi R, et al. Chronic paracoccidioidomycosis in a female patient in Austria. Eur J Clin Microbiol Infect Dis. Dec 2004;23(12):916-9. [Medline].
Maluf ML, Pereira SR, Takahachi G, Svidzinski TI. [Prevalence of paracoccidioidomycosis infection determined by sorologic test in donors' blood in the Northwest of Parana, Brazil]. Rev Soc Bras Med Trop. Jan-Feb 2003;36(1):11-6. [Medline].
Cabral-Marques O, Schimke LF, Pereira PV, Falcai A, de Oliveira JB, Hackett MJ, et al. Expanding the Clinical and Genetic Spectrum of Human CD40L Deficiency: The Occurrence of Paracoccidioidomycosis and Other Unusual Infections in Brazilian Patients. J Clin Immunol. Dec 23 2011;[Medline].
Nogueira LM, Santos M, Ferreira LC, Talhari C, Rodrigues RR, Talhari S. AIDS-associated paracoccidioidomycosis in a patient with a CD4+ T-cell count of 4 cells/mm³. An Bras Dermatol. Jul-Aug 2011;86(4 Suppl 1):S129-32. [Medline].
Desjardins CA, Champion MD, Holder JW, Muszewska A, Goldberg J, Bailão AM, et al. Comparative genomic analysis of human fungal pathogens causing paracoccidioidomycosis. PLoS Genet. Oct 2011;7(10):e1002345. [Medline]. [Full Text].
Blotta MH, Mamoni RL, Oliveira SJ, et al. Endemic regions of paracoccidioidomycosis in Brazil: a clinical and epidemiologic study of 584 cases in the southeast region. Am J Trop Med Hyg. Sep 1999;61(3):390-4. [Medline].
Pereira RM, Tresoldi AT, da Silva MT, Bucaretchi F. Fatal disseminated paracoccidioidomycosis in a two-year-old child. Rev Inst Med Trop Sao Paulo. Jan-Feb 2004;46(1):37-9. [Medline].
Sant'Anna GD, Mauri M, Arrarte JL, Camargo H Jr. Laryngeal manifestations of paracoccidioidomycosis (South American blastomycosis). Arch Otolaryngol Head Neck Surg. Dec 1999;125(12):1375-8. [Medline].
de Almeida SM, Queiroz-Telles F, Teive HA, Ribeiro CE, Werneck LC. Central nervous system paracoccidioidomycosis: clinical features and laboratorial findings. J Infect. Feb 2004;48(2):193-8. [Medline].
Corti M, Villafane MF, Negroni R, Palmieri O. Disseminated paracoccidioidomycosis with peripleuritis in an AIDS patient. Rev Inst Med Trop Sao Paulo. Jan-Feb 2004;46(1):47-50. [Medline].
Marques da Silva SH, Queiroz-Telles F, Colombo AL, Blotta MH, Lopes JD, Pires De Camargo Z. Monitoring gp43 antigenemia in Paracoccidioidomycosis patients during therapy. J Clin Microbiol. Jun 2004;42(6):2419-24. [Medline].
Yasuda MA. Pharmacological management of paracoccidioidomycosis. Expert Opin Pharmacother. Mar 2005;6(3):385-97. [Medline].
da Silva SH, Grosso Dde M, Lopes JD, et al. Detection of Paracoccidioides brasiliensis gp70 circulating antigen and follow-up of patients undergoing antimycotic therapy. J Clin Microbiol. Oct 2004;42(10):4480-6. [Medline].
Hay RJ. Antifungal drugs used for systemic mycoses. Dermatol Clin. Jul 2003;21(3):577-87. [Medline].
Queiroz-Telles F, Goldani LZ, Schlamm HT, Goodrich JM, Espinel-Ingroff A, Shikanai-Yasuda MA. An open-label comparative pilot study of oral voriconazole and itraconazole for long-term treatment of paracoccidioidomycosis. Clin Infect Dis. Dec 1 2007;45(11):1462-9. [Medline].
Travassos LR, Taborda CP, Colombo AL. Treatment options for paracoccidioidomycosis and new strategies investigated. Expert Rev Anti Infect Ther. Apr 2008;6(2):251-62. [Medline].
Ollague JM, de Zurita AM, Calero G. Paracoccidioidomycosis (South American blastomycosis) successfully treated with terbinafine: first case report. Br J Dermatol. Jul 2000;143(1):188-91. [Medline].
Crissey JT, Lang H, Parish LC. Manual of Medical Mycology. Cambridge, Mass: Blackwell Sciences; 1995:128-34.
Elder D, Elenitsas E, Jawarsky C, et al, eds. Lever's Histopathology of the Skin. 10th ed. Philadelphia, Pa: Lippincott-Raven; 2008.
Guerrant RL, Walker DH, Weller PF, eds. Tropical Infectious Diseases: Principles, Pathogens, and Practice. 2nd ed. New York, NY: Churchill Livingstone; 2006.
Richardson MD, Warnock DW, eds. Fungal Infection: Diagnosis and Management. 3rd ed. London, England: Bailliere Tindallk; 2003.
Stickland GT, ed. Hunter's Tropical Medicine and Emerging Infectious Diseases. 8th ed. Philadelphia, Pa: WB Saunders; 2000:559-61.

