Case Study: Primary Cutaneous Blastomycosis

Primary cutaneous blastomycosis
The physical examination showed numerous verrucous nodules and plaques with overlying crusting and surrounding erythema on the left lower back and buttock (Panel A). Grocott–Gomori methenamine silver staining showed broad-based budding fungal organisms (Panel B)

Case of primary cutaneous blastomycosis in 53-year-old

This article describes the case of a 53-year-old male patient diagnosed with primary cutaneous blastomycosis. The patient presented to the clinic with the complaint of a 4-month history of red, raised and itchy skin lesions on the left upper back and buttock. The patient’s medical history was not significant for constitutional or respiratory symptoms. He worked as a landscaper and was at a high risk of skin abrasions while trimming trees.

Physical examination was significant for numerous verrucous nodules and plaques

Physical examination was significant for numerous verrucous nodules and plaques on the left lower back and buttock with crusting and surrounding erythema. Doctors further advised histopathological analysis which showed pseudoepitheliomatous hyperplasia with intraepidermal and dermal infiltrate. The infiltrate was composed of neutrophils, eosinophils, histocytes, lymphocytes, multinucleated giant cells and granuloma formation. Grocott-Gomori methenamine silver staining further showed a budding fungal organism. However, there were no signs of abnormalities on the chest imaging. These findings are consistent with Blastomyces dermatitidis. The patient was further referred for a urine antigen test for Blastomyces which was also positive. Whereas chest imaging did not show any abnormalities.

Based on the findings, the patient was diagnosed with primary cutaneous blastomycosis. Primary cutaneous blastomycosis is caused by blastomyces species, which is a dimorphic fungus found in the eastern half of the United States. The fungi are endemic in the U.S. and Canada and typically grow in soil and detritus from wooden areas. As with this case, the patient is a landscaper. Cutaneous manifestations are an indication of disseminated disease. While rare, the disease may occur by means of primary inoculation. Treatment included itraconazole therapy for 6 months after which the skin lesions resolved completely [1].

Primary cutaneous blastomycosis

Exposure to the fungi generally occurs in moist wooded areas when the microhabitats that live in the soil are disturbed because of certain activities. Inhaled conidia can cause a primary lung infection that may become disseminated. Blastomycosis most commonly presents as pulmonary disease. Whereas isolated lung disease may occur in 60 to 75% of infected people. Blastomycosis may also disseminate to the skin. bone, genitourinary and other organ systems. In fewer than 10% of the cases, blastomycosis can manifest as acute respiratory distress syndrome (ARDS) with a systemic presentation, hypoxemia, tachypnea and dyspnoea. A review of the reports showed that in 33 patients with ARDS secondary to blastomycosis, 21 deaths occurred [2]. Although the exact mechanism of the disease is not yet known, the high mortality rate can be because of systemic stimulation of inflammatory mediators.

Morbidity and mortality can be reduced with prompt therapy

Studies have shown that systemic stimulation of inflammatory mediators is a reasonable explanation for the high mortality rate in 40 to 60% of cases. Morbidity and mortality can be reduced with prompt therapy. Thus, the suspicion of disseminated disease is especially helpful for the early detection of disease in endemic areas. Blastomycosis rarely presents as a primary cutaneous lesion after traumatic inoculation from outdoor trauma, animal bites or scratches, laboratory or autopsy exposure. The clinical presentation, however, varies. Symptoms of the infection may either be absent, acute, chronic or fulminant. In many cases, primary cutaneous blastomycosis often mimics other conditions such as bacterial pyoderma, leprosy, tertiary syphillis, tuberculosis, squamous cell carcinoma and keratoacanthoma.

A thorough history and physical examination is useful for making correct clinical and diagnostic decisions

Blastomycosis is a serious infection that may resemble other condition, this when assessing patients with skin and pulomary infections, a high index of suspicion of B. dermatitidis is necessary in endemic areas. A thorough history and physical examination is useful for making correct clinical and diagnostic decisions when patients present with symptoms consistent with primary cutaneous blastomycosis. This article describes the case of a landscaper with cutaneous lesions on the left upper back and buttock that resolved with 6 months of treatment. While its rare, progression of the cutaneous lesions to ARDS can have severe consequences and lead to mortality. Prompt therapy with antifungals and steroids can show an improved outcome.

In conclusion, accurate diagnosis heavily relies on a high level of clinical suspicion and laboratory investigations. Whereas a favourable treatment outcome is based on appropriate therapy.


Alhatem, A. and Smith, K.C., 2022. Primary Cutaneous Blastomycosis. The New England Journal of Medicine386(18), pp.e49-e49.

Emer, J.J. and Spear, J.B., 2009. Primary cutaneous blastomycosis as a cause of acute respiratory distress syndrom: case report and literature review. The Journal of Clinical and Aesthetic Dermatology2(3), p.22.

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Dr. Aiman Shahab is a dentist with a bachelor’s degree from Dow University of Health Sciences. She is an experienced freelance writer with a demonstrated history of working in the health industry. Skilled in general dentistry, she is currently working as an associate dentist at a private dental clinic in Karachi, freelance content writer and as a part time science instructor with Little Medical School. She has also been an ambassador for PDC in the past from the year 2016 – 2018, and her responsibilities included acting as a representative and volunteer for PDC with an intention to make the dental community of Pakistan more connected and to work for benefiting the underprivileged. When she’s not working, you’ll either find her reading or aimlessly walking around for the sake of exploring. Her future plans include getting a master’s degree in maxillofacial and oral surgery, settled in a metropolitan city of North America.


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