Cutaneous Blastomycosis: Symptoms and Treatment

Cutaneous blastomycosis is an uncommon yet significant manifestation of blastomycosis, a systemic fungal infection caused by Blastomyces dermatitidis. 

---

What Is Cutaneous Blastomycosis?

Cutaneous blastomycosis refers to the skin involvement in the context of a blastomycosis infection. Unlike pulmonary blastomycosis, which primarily affects the lungs, cutaneous blastomycosis manifests on the skin, either as a primary infection or more commonly, as a secondary dissemination from a primary pulmonary site.

---

Causes of Cutaneous Blastomycosis

The etiological agent, Blastomyces dermatitidis, is a dimorphic fungus endemic to specific geographical regions such as the Midwestern, South Central, and Southeastern United States. The fungus thrives in moist soil and decaying organic matter. Human infection occurs through inhalation of airborne spores, which may disseminate hematogenously to the skin, resulting in cutaneous manifestations.

---

Symptoms of Cutaneous Blastomycosis

Cutaneous blastomycosis presents with a range of dermatological symptoms that may resemble other skin conditions, complicating its diagnosis. The most common symptoms include:

Skin Lesions

Skin lesions are the hallmark of cutaneous blastomycosis. These lesions can vary in appearance but are typically verrucous, ulcerative, or nodular. They may appear as single or multiple lesions on exposed areas such as the face, neck, and extremities. The lesions can be painful and may discharge pus or other exudates.

Secondary Symptoms

Additional symptoms may include systemic signs such as fever, malaise, and weight loss, particularly in cases where the infection has disseminated from a pulmonary site. It's essential for clinicians to consider the systemic nature of blastomycosis when evaluating skin lesions that do not respond to conventional treatments.

---

Cutaneous Blastomycosis vs. Pulmonary Blastomycosis

Understanding the distinction between cutaneous and pulmonary blastomycosis is crucial for accurate diagnosis and management.

Pulmonary Blastomycosis

Pulmonary blastomycosis primarily affects the lungs and presents with respiratory symptoms such as cough, chest pain, and shortness of breath. While it can remain confined to the respiratory system, dissemination to the skin and other organs is possible, leading to cutaneous manifestations.

Cutaneous Manifestations

In cutaneous blastomycosis, the skin lesions are often the first and most prominent signs of the disease. Unlike pulmonary blastomycosis, the respiratory symptoms may be absent or less pronounced when the infection presents primarily in the skin.

---

Diagnosis of Cutaneous Blastomycosis

Accurate diagnosis of cutaneous blastomycosis requires a high index of suspicion, particularly in endemic regions or in patients with a history of travel to such areas.

Clinical Examination

A thorough clinical examination is essential. Dermatological evaluation of the lesions, considering their characteristic appearance, can provide initial clues.

Laboratory Tests

Definitive diagnosis is confirmed through laboratory tests, which may include:

---

Treatment of Cutaneous Blastomycosis

Effective management of cutaneous blastomycosis hinges on appropriate antifungal therapy.

Antifungal Medications

The primary treatment for cutaneous blastomycosis involves antifungal medications. The choice of antifungal agent and duration of therapy depend on the severity of the infection and whether there is systemic involvement.

Monitoring and Follow-Up

Regular monitoring of treatment response is critical. Follow-up visits should assess lesion resolution and any potential side effects from antifungal therapy. In cases of recurrent or refractory infections, further investigation and adjustment of treatment may be required.

---

Prevention and Prognosis

Preventing cutaneous blastomycosis involves minimizing exposure to environments where Blastomyces dermatitidis is prevalent. Individuals at risk, such as those engaged in outdoor activities in endemic areas, should take precautions such as wearing protective clothing and masks to reduce inhalation of spores.

The prognosis for cutaneous blastomycosis is generally favorable with timely diagnosis and appropriate treatment. However, delayed treatment or misdiagnosis can lead to complications, including chronic skin lesions and systemic dissemination.