A case of blastomycosis presenting as a non-healing unifocal ulcerative nodule on the jawline

Blastomyces dermatitidis is a dimorphic fungus that can disseminate in the immunocompetent and immunodeficient. Many infected patients display heterogenous cutaneous findings, making it one of dermatology's great clinical mimics. Cases presenting as single lesions are often mistaken for neoplasms or other infections. We report a patient with diabetes mellitus who presented to the emergency department with a two-month history of an ulcerated jawline nodule. Treatment with incision/drainage and doxycycline for presumed bacterial abscess was unsuccessful. Upon re-presentation 10 days later, biopsy and fungal culture of the tumor confirmed infection with B. dermatitidis. Chest computed tomography revealed disease dissemination. Halfway through a 6-month course of itraconazole, cutaneous and pulmonary findings were notably improved. Diabetes is an emerging risk factor for dissemination that likely contributed to the severity in our case. Early biopsy can prevent potentially life-threatening treatment delays, highlighting the need for blastomycosis to be considered in the differential diagnosis of non-healing wounds.