Case Reports

North American Blastomycosis in an Immunocompromised Patient

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Blastomycosis is a subacute or chronic deep mycosis caused by a dimorphic fungus, Blastomyces dermatitidis, that generally produces a pulmonary form of the disease and, to a lesser extent, extrapulmonary forms, such as cutaneous, osteoarticular, and genitourinary. Both immunocompetent and immunocompromised individuals can be infected, but more severe disease occurs in the immunocompromised. Blastomycosis can be diagnosed by culture, direct visualization of the yeast in affected tissue, antigen testing, or a combination of these methods. Treatment course and duration depend on the severity of illness. For mild to moderate pulmonary disease, treatment is itraconazole. For severe blastomycosis, lipid-formulation amphotericin B is given, followed by itraconazole. We present an interesting case of cutaneous blastomycosis acquired in Atlanta, Georgia, that looks quite similar to other mycoses, such as coccidioidomycosis and sporotrichosis, and describe its distinguishing features.

Practice Points

  • Blastomycosis generally produces a pulmonary form of the disease and, to a lesser extent, extrapulmonary forms, such as cutaneous, osteoarticular, and genitourinary.
  • Blastomycosis can be diagnosed by culture, direct visualization of the yeast in affected tissue, antigen testing, or a combination of these methods.
  • After inhalation of Blastomyces dermatitidis spores, which are taken up by bronchopulmonary macrophages, there is an approximate 30- to 45-day incubation period.


 

References

Blastomycosis is a systemic fungal infection that is endemic in the South Central, Midwest, and southeastern regions of the United States, as well as in provinces of Canada bordering the Great Lakes. After inhalation of Blastomyces dermatitidis spores, which are taken up by bronchopulmonary macrophages, there is an approximate 30- to 45-day incubation period. The initial response at the infected site is suppurative, which progresses to granuloma formation. Blastomyces dermatitidis most commonly infects the lungs, followed by the skin, bones, prostate, and central nervous system (CNS). Therapy for blastomycosis is determined by the severity of the clinical presentation and consideration of the toxicities of the antifungal agent.

We present the case of a 38-year-old man with a medical history of human immunodeficiency virus (HIV) infection and AIDS who reported a 3- to 4-week history of respiratory and cutaneous symptoms. Initial clinical impression favored secondary syphilis; however, after laboratory evaluation and lack of response to treatment for syphilis, further investigation revealed a diagnosis of widespread cutaneous North American blastomycosis.

Case Report

A 38-year-old man with a medical history of HIV infection and AIDS presented to the emergency department at a medical center in Minneapolis, Minnesota, with a cough; chest discomfort; and concomitant nonpainful, mildly pruritic papules and plaques of 3 to 4 weeks’ duration that initially appeared on the face and ears and spread to the trunk, arms, palms, legs, and feet. He had a nonpainful ulcer on the glans penis. Symptoms began while he was living in Atlanta, Georgia, before relocating to Minneapolis. A chest radiograph was negative.

The initial clinical impression favored secondary syphilis. Intramuscular penicillin G benzathine (2.4 million U) weekly for 3 weeks was initiated by the primary care team based on clinical suspicion alone without laboratory evidence of a positive rapid plasma reagin or VDRL test. Because laboratory evaluation and lack of response to treatment did not support syphilis, dermatology consultation was requested.

The patient had a history of crack cocaine abuse. He reported sexual activity with a single female partner while living in a halfway house in the Minneapolis–St. Paul area. Physical examination showed an age-appropriate man in no acute distress who was alert and oriented. He had well-demarcated papules and plaques on the forehead, ears, nose, cutaneous and mucosal lips, chest, back, arms, legs, palms, and soles. Many of the facial papules were pink, nonscaly, and concentrated around the nose and mouth; some were umbilicated (Figure 1). Trunk and extensor papules and plaques were well demarcated, oval, and scaly; some had erosions centrally and were excoriated. Palmar papules were round and had peripheral brown hyperpigmentation and central scale (Figure 2). A 1-cm, shallow, nontender, oval ulceration withraised borders was located on the glans penis under the foreskin (Figure 3).

Figure 1. Pink nonscaly facial papules around the nose and mouth


Figure 2. Palmar papules with peripheral brown hyperpigmentation and central scale.

Figure 3. Shallow nontender oval ulceration (1 cm) on the glans penis

A rapid plasma reagin test was nonreactive; a fluorescent treponemal antibody absorption test was negative. Chest radiograph, magnetic resonance imaging, and electroencephalogram were normal. In addition, spinal fluid drawn from a tap was negative on India ink and Gram stain preparations and was negative for cryptococcal antigen. In addition, spinal fluid was negative for fungal and bacterial growth, as were blood cultures.

Abnormal tests included a positive enzyme-linked immunosorbent assay and Western blot test for HIV, with an absolute CD4 count of 6 cells/mL and a viral load more than 100,000 copies/mL. Urine histoplasmosis antigen was markedly elevated. A potassium hydroxide preparation was performed on the skin of the right forearm, revealing broad-based budding yeast, later confirmed on skin and sputum cultures to be B dermatitidis.

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