Sporotrichosis
Rose-gardener's disease; sporotrichoid lymphocutaneous infection; Sporothrix schenckii infection
Sporotrichosis is a deep mycotic infection caused by the dimorphic fungus Sporothrix schenckii complex (including S. brasiliensis, S. globosa, S. luriei, S. mexicana). It is the prototypical cause of sporotrichoid lymphocutaneous spread — a primary inoculation nodule at the site of plant / soil trauma followed by a chain of subcutaneous nodules ascending along lymphatic drainage. Rose-gardener's disease is the classic exposure history. UK cases are sporadic, often in returning travellers from endemic areas (Latin America, southern Africa, South-East Asia). Itraconazole 100–200 mg daily for 3–6 months is the standard first-line therapy.
Clinical features
- Primary inoculation nodule — small red-brown papule at site of plant / thorn / splinter trauma; develops 1–10 weeks after inoculation.
- Lesion enlarges to a non-healing ulcer or violaceous nodule.
- Sporotrichoid lymphocutaneous spread — secondary nodules at intervals along the lymphatic drainage of the affected limb, often appearing weeks after the primary.
- Lymphadenopathy uncommon.
- Constitutional symptoms uncommon in immunocompetent hosts.
- Fixed cutaneous form — single non-spreading lesion (more common in endemic populations).
- Extracutaneous and disseminated disease — pulmonary, osteoarticular, ocular, CNS — in immunosuppressed (HIV, transplant, alcohol).
Differential for sporotrichoid spread
- Atypical mycobacterial infection (M. marinum, M. chelonae).
- Nocardia brasiliensis.
- Cutaneous leishmaniasis.
- Cat-scratch disease (Bartonella).
- Tularaemia.
- Cutaneous tuberculosis (especially scrofuloderma).
- Pyoderma gangrenosum (rare lymphocutaneous variant).
- Inflammatory or hypersensitivity reactions.
- Cancers — KA, cSCC (less likely to be multifocal).
Diagnosis
- Detailed exposure history — gardening, sphagnum moss, rose handling, hay, returning traveller.
- Skin biopsy with split tissue:
- Histology — granulomatous inflammation, sometimes with characteristic asteroid bodies (rare). Cigar-shaped yeasts seen in tissue (variable yield).
- Microbiology — fungal culture on Sabouraud agar at 25 °C and 37 °C (dimorphic — mould at 25, yeast at 37). Culture is the gold standard.
- PCR — emerging where culture access limited.
- Serological tests have limited utility.
- Imaging — for osteoarticular extension if joint symptoms; CXR for pulmonary disease in immunosuppressed.
Management
- First-line — itraconazole 100–200 mg daily for 3–6 months, continued until 1–2 months after clinical resolution.
- Alternative — terbinafine 250–500 mg daily; potassium iodide solution (oldest treatment, less tolerable).
- Disseminated / severe disease — amphotericin B (liposomal preferred) initially, transition to itraconazole maintenance.
- Pregnancy — limited safe options; specialist input. Local heat therapy historically used.
- Topical / intralesional therapy — limited role; surgical excision rarely indicated.
- Follow-up — until at least one month after complete clinical resolution; recurrence rate ~ 5–10%.
References
- Kauffman CA et al. Clinical practice guidelines for the management of sporotrichosis — IDSA. Clin Infect Dis; 2007.
- Chakrabarti A et al. Global epidemiology of sporotrichosis. Med Mycol; 2015.
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