Pediatric Blastomycosis Clinical Presentation

The clinical spectrum of blastomycosis widely varies, including asymptomatic infection (in nearly one half of patients infected), acute or chronic pneumonia, and extrapulmonary disease.

Most cases of blastomycosis are sporadic. Nearly one half of patients infected may be asymptomatic. In one study involving 46 children and 2 adults, symptoms began 21-106 days (median 45 d) after exposure to the pathogen in a beaver pond.^[4] Patients may complain of an influenzalike illness with the following nonspecific constitutional symptoms:

• Fever
• Chills
• Night sweats
• Weight loss
• Malaise
• Myalgia

Acute pulmonary infection is the most frequent presentation of blastomycosis in children. Symptoms include the following:

• Productive cough
• Dyspnea
• Wheezing
• Chest pain
• Hemoptysis (rarely)

Symptoms of chronic pneumonia may last for 2-6 months and include weight loss, night sweats, fever, cough, and chest pain. Most adult patients diagnosed with blastomycosis have an indolent onset of chronic pneumonia.

Signs of acute or chronic pneumonia may be noted. Life-threatening progressive lung disease and disseminated infection can occur in 10% of reported cases.

Disseminated blastomycosis usually begins with pulmonary infection followed by cutaneous, osseous, genitourinary, or CNS involvement.

Less commonly, primary cutaneous blastomycosis may follow after traumatic inoculation of the fungus into the skin (see the image below).

Extrapulmonary disease in blastomycosis includes the following:

• Skin, most commonly (25%)
• Bone (25%)
• Prostatitis or epididymitis (17%): This is a common manifestation in adults and is not reported in prepubescent children.
• Neurologic involvement: This occurs in 3-5% of extrapulmonary infections and is manifested as intracranial or epidural abscesses and, rarely, meningitis.

Skin lesions are the most common manifestation of extrapulmonary disease. Cutaneous lesions favor exposed areas and enlarge over many weeks, from pimples that are minimally tender to well-circumscribed verrucous or ulcerative lesions, often with little inflammation. Verrucous lesions demonstrate raised irregular borders with crusting and purulent drainage, whereas ulcerative lesions are characterized by sharp and heaped-up borders with centrally located granulation tissue and exudate.

Osteolytic lesions may occur in nearly any bone and present as a cold abscess or draining sinus.

Extension to a contiguous joint may result in indolent swelling, pain, and restriction of movement. The vertebra, skull, ribs, and long bones are most commonly affected.

Intrauterine or congenital infections are unusual.

Other unusual metastatic sites of infection include larynx, reticuloendothelial system (liver, spleen, lymph nodes, bone marrow), oropharynx, nose, and thyroid.

B dermatitidis is a thermal dimorphic fungus that occurs in mycelial form in nature and as yeast in infected tissue.

• The fungus grows on Sabouraud agar at room temperature (250°C) as a white fluffy mold. Alternatively, at body temperature (37°C) and on blood agar, the fungus forms a brown wrinkled colony.
• The mycelial form of B dermatitidis has been isolated from soil, although its ecologic niche is not characterized as well as other endemic fungi.
• Inhalation of the microconidia from the mold form of B dermatitidis into the lungs leads to infection.
• In infected tissue specimens, B dermatitidis appears as a characteristic thick-walled yeast cell (8- to 15-mcg diameter) with broad-based daughter cells.