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Subcutaneous Mycoses

ICD-9: 117.9 ○ ICD-10: B48.8

  • A heterogeneous group of fungal infections that develop at the sites of transcutaneous trauma.

  • Sporotrichosis

  • Phaeohyphomycoses:

    • Eumycetoma

    • Chromoblastomycosis

  • Etiology. Fungi resident on plants or in soil

    • Melanin-producing (dematiaceous or pigmented): brown to black

    • Nonpigmented (hyaline)

  • Clinical Manifestations. Slowly enlarging plaques with verrucous lesions, fistulae, sinuses, and scarring, most commonly on lower extremity; can occur at any site of inoculation.

  • Host Defense Defect. Infections more extensive. Can disseminate.

  • Diagnosis. Clinical findings, demonstration of grains or Medlar bodies, dermatopathology, culture of organism.

Sporotrichosis

ICD-9: 117.1 ○ ICD-10: B42 Image not available.

  • Etiology. Sporothrix schenckii. Infection follows accidental inoculation of skin.

  • Clinical Manifestations

    • Nodule or plaque at inoculation site infection.

    • Lymphangitis. Chronic nodular lymphangitis (sporotrichoid lymphocutaneous syndrome.

    • Subcutaneous swelling occurs proximal to inoculation site.

    • Disseminated infection can occur from skin or pulmonary infection with host defense defects.

Etiology and Epidemiology

Etiology

S. schenckii, a thermally dimorphic fungus. Tissue form is an oval, cigar-shaped yeast. Lives as a saprophyte on plants. Worldwide distribution. More common in temperate, tropical zones.

Demography

Occupational exposure important: Agricultural and forest workers, gardeners, farmers, lawn laborers, florists, paper manufacturers, and gold miners. In Uruguay, 80% of cases occur after a scratch by an armadillo.

Transmission

Cutaneous puncture or small abrasion. Zoonosis: Rarely transmitted from cats with sporotrichosis to humans; armadillos.

Pathogenesis

After subcutaneous inoculation, S. schenckii grows locally forming plaque sporotrichosis and can extend proximally to nodular lymphangitis.

Clinical Manifestation

Incubation period 3 weeks (range, 3 days to 12 weeks) after trauma or injury to site of lesion. Lesions are relatively asymptomatic, painless. Afebrile.

Fixed Cutaneous (Plaque) Sporotrichosis

Dermal papule, pustule, or nodule appears at inoculation site several weeks after injury. May enlarge to verrucous plaque or ulcer with induration. Draining lymph nodes become inflamed and enlarged (chancriform syndrome). Distribution: Primary lesion most common on dorsum of hand or finger. Fixed plaque: face in children; upper extremities in adults.

Nodular Lymphangitis

Follows proximal lymphatic extension from inoculation site. Red nodules form in intervening lymphatics; may become indurated, nodular, thickened. Distribution: Inoculation nodule on hand/finger with nodular lymphangiitis extending proximally on arm (Figs. C-1 and C-2).

Figure C-1.

Sporotrichosis: nodular lymphangitic type A 78-year-old gardener with tender nodules on hand and arm for 4 weeks. Erythematous nodules in a linear array in lymphatic channels on the dorsum of the hand and forearm. S. schenckii was isolated on culture of a lesional biopsy specimen.

Figure C-2.

Sporotrichosis: chronic lymphangitic type An erythematous ...

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