However, commercial antigen tests have a high degree of cross-reactivity with other endemic fungal conditions such as histoplasmosis, and thus cannot distinguish blastomycosis from other similar conditions. This cross-reactivity is caused by these related fungal organisms using similar galactomannans in the cell wall.While culture of the Blastomyces organism remains the definitive diagnostic standard, its slow growing nature can lead to a delay of up to four weeks. In addition, sometimes blood and sputum cultures may not detect blastomycosis. Cultures of the cerebrospinal fluid also have poor sensitivity compared to histopathological examination of the affected tissue. Treatment
Under Infectious Disease Society of America guidelines, severe cases of blastomycosis and cases with central nervous system (CNS) involvement are treated initially with amphotericin B, followed by a lengthy course of an azole drug such as itraconazole. In most cases the amphotericin treatment lasts for 1–2 weeks, but in cases of CNS involvement it may last for up to 6 weeks. Cases that do not require amphotericin B treatment are treated with a lengthy course of an azole drug.Among azole drugs, itraconazole is generally the treatment of choice. Voriconazole is often recommended for CNS blastomycosis cases due to its ability to pass the blood-brain barrier. Other azole drugs that may be used include fluconazole. Ketoconazole was the azole drug first used for blastomycosis treatment, but has been largely replaced by itraconazole because ketoconazole is less effective and less tolerated by patients. The azole treatment generally lasts for a minimum of six months. Cure rates from itraconazole treatment are nearly 95%.
In most such cases, the infection in the dog becomes apparent before the human infection. This may be due to a shortened incubation period, caused by the dog inhaling larger quantities of Blastomyces spores than the human.In veterinary care, blastomycosis is typically treated with itraconazole. 70% of treated dogs respond to medication and recover. In dogs as in humans, the prognosis for blastomycosis depends on the severity of the symptoms. Additional images
See also
Histoplasmosis
Paracoccidioidomycosis

References
Further reading
Castillo CG, Kauffman CA, Miceli MH (2016). "Blastomycosis". Infectious Disease Clinics of North America. 30 (1): 247–264. doi:10.1016/j.idc.2015.10.002. PMID 26739607. (Review). McBride JA, Gauthier GM, Klein BS (2017). "Clinical Manifestations and Treatment of Blastomycosis". Clinics in Chest Medicine. 38 (3): 435–449. doi:10.1016/j.ccm.2017.04.006. PMC 5657236. PMID 28797487. PMC 5657236 (Review)

External links

 Media related to Blastomycosis at Wikimedia Commons
Blastomyces at the US National Library of Medicine Medical Subject Headings (MeSH)
NIH Encyclopedia Blastomycosis