Blastomycosis: The great pretender can also be an opportunist. Initial clinical diagnosis and underlying diseases in 123 patients.

Clinically, blastomycosis can be difficult to recognize even in the endemic areas where clinicians are aware of this problem. In only 18% of 123 patients from the University of Mississippi Medical Center (Jackson, MS) blastomycosis was correctly suspected at the initial patient evaluation. Pneumonia sensu latu (40%), malignant tumors (16%), and tuberculosis (14%) were the most common misdiagnoses. The false first impression frequently resulted in unnecessary surgeries or treatment delays, with patients receiving inefficient antibiotic therapy for months. The presence of cutaneous involvement by the disease makes its' recognition easier for the clinician, raising the percentage of correct initial diagnosis to 64%. To evaluate the association with immunodepression, the presence of other diseases was also searched among the 123 patients. An immunodepressive condition preceded the fungal disease in 25% of patients. Another associated disease commonly found in blastomycotic patients was diabetes mellitus (22%). Blastomycosis is correctly suspected at the first clinical evaluation in only a small percentage of patients; pneumonia, cancer, and tuberculosis are the most common clinical considerations. Cutaneous involvement leads the clinician to the correct diagnosis in the majority of cases. One fourth of the patients with blastomycosis had underlying immunodepressive conditions, and underlying diabetes mellitus is present in 22% of patients.