Sporotrichosis
Sporotrichosis is a subacute fungal infection caused by direct cutaneous inoculation of the dimorphic fungus Sporothrix schenckii, classically from a rose thorn or plant matter, producing a nodular ulcer that spreads along lymphatic channels; diagnosis requires culture of the organism, and itraconazole is first-line treatment for cutaneous and lymphocutaneous disease.
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What this article covers
- Overview
A subacute cutaneous and lymphocutaneous mycosis caused by direct inoculation, not inhalation: sporotrichosis follows traumatic implantation of Sporothrix schenckii, a dimorphic fungus, into the skin or subcutaneous tissue.
- Epidemiology
Worldwide distribution with the highest burden in the Americas and Japan: most reported infections originate in North and South America and Japan, reflecting regional soil and plant reservoirs of the organism.
- Risk factors
Direct skin trauma with plant material, especially rose thorns: the single most important risk factor is a penetrating or abrading injury that inoculates the organism into skin or subcutaneous tissue.
- Pathophysiology
Traumatic inoculation introduces the mycelial form into tissue: at ambient/room temperature the organism grows as a mold with hyphae; injury delivers conidia or hyphal fragments directly into the…
- Clinical features
A single papulonodular lesion at the site of inoculation, evolving over days to weeks: a small, painless or mildly tender papule enlarges into a nodule, then ulcerates and develops a crusted…
- Differential diagnosis
Mycobacterium marinum infection: produces an identical sporotrichoid pattern of ascending nodules after aquarium or fish-tank exposure; the discriminator is an aquarium/fish exposure history plus a…
- Diagnosis
Sporotrichosis is confirmed by fungal culture of the organism from affected tissue, exudate, or biopsy material; clinical recognition of the lesion pattern alone is insufficient to establish the diagnosis.
- Management
Confirm the diagnosis by culture before starting prolonged antifungal therapy, since treatment courses run for months.
- Complications
Extension to deeper structures at the inoculation site: tenosynovitis, septic arthritis, or osteomyelitis, particularly with a rose-thorn injury near a joint.
- Prognosis
Cutaneous and lymphocutaneous disease has an excellent prognosis with appropriate antifungal therapy: itraconazole cures the great majority of cases when the full 3- to 6-month course is completed.
- Prevention
Wear protective gloves and long sleeves when handling roses, thorny plants, hay, straw, or sphagnum moss: the single most effective measure, since inoculation requires direct penetrating contact with contaminated plant material.
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