Subcutaneous Mycoses: Sporotrichosis & Chromomycosis

• Subcutaneous mycoses are fungal infections affecting the dermis, subcutaneous tissue, and bone.
• Causative organisms are found in soil, decaying vegetation, or live plants.

Sporotrichosis

• Caused by Sporothrix schenckii, a dimorphic fungus (yeast and mold).
• The yeast form appears in infected tissue.
• The mold form appears when cultured in a laboratory.
• Associated with rose bushes, hay, and other plant materials.
• Risk factor includes open cuts or wounds on the skin.
• It begins with a primary ulcer at the puncture site.
• Secondary lesions may appear along the draining lymphatic pathways.
• Often self-limiting, but can become chronic.
• Dissemination to distant sites is possible in immunocompromised patients (e.g., AIDS).
• Oral itraconazole is the preferred treatment.
• Typical infection sites include legs, feet, and hands.

Chromomycosis

• Caused by several species of pigmented soil fungi, including Phialophora and Cladophialophora.
• These fungi are dematiaceous, containing dark-colored, gray, or black hyphae.
• The infection is introduced through skin trauma.
• Most commonly seen in tropical regions.
• Characterized by slow-spreading, wart-like nodules along the lymphatic vessels.
• Nodules may develop into crusting abscesses.
• Can cause scarring and fibrosis.
• Treatment is difficult, advanced stages require itraconazole or voriconazole, alongside local surgery.

Mycetoma (Madura Foot)

• Caused by various soil fungi, most commonly Madurella species and Exophiala species.
• Enters through wounds on the feet, hands, or back.
• Initially presents as an abscess, usually on the foot.
• The abscess discharges serum and blood through sinus tracts.
• Can spread to underlying bone, leading to deformities.
• Lesions resemble chromomycosis, but mycetoma has colored grains composed of hyphae in the exudate.
• Treatment typically involves surgical excision.
• There is no effective antifungal chemotherapy.