Endemic mycosis with worldwide distribution caused by the dimorphic fungus Sporothrix schenckii.
The vast majority of sporotrichosis infections are lymphocutaneous or fixed cutaneous forms, although osteoarticular, pulmonary, meningeal, and disseminated sporotrichosis may occur, especially in patients with diabetes, alcoholism, HIV, and hematologic malignancies, but also in normal hosts.
Lymphocutaneous sporotrichosis is caused by traumatic inoculation of the fungus into the skin and results in an initial nodular lesion that usually ulcerates, which is followed by ascending nodular lymphangitis.
The definitive test for diagnosis of lymphocutaneous sporotrichosis is culture of the fungus from skin lesions.
Because of their nonspecific presentation and relative rarity, a high index of clinical suspicion is required for diagnosis of extracutaneous forms of sporotrichosis, which is typically delayed.
Lymphocutaneous sporotrichosis is not life threatening and responds well to itraconazole treatment.
Extracutaneous manifestations of sporotrichosis can be life threatening, especially in immunosuppressed patients, and do not always favorably respond to antifungal therapy.
Sporotrichosis is most often localized in the skin and subcutaneous tissues, following traumatic inoculation of the causative fungus Sporothrix to the dermis of individuals with outdoor vocations and occupations. More than 95% of sporotrichosis cases are caused by the Sporothrix schenckii complex, including S schenckii sensu strictu and several cryptic species, which are identified in the routine laboratory as S schenckii.
History and exam
Key diagnostic factors
- primary skin lesion
- nodular lymphangitis lesions
Other diagnostic factors
- respiratory symptoms
- joint swelling/erythema
- male 30 to 60 years old
- meningitis-like symptoms
- trauma to the skin
- outdoor occupation/hobbies
- animal bites and scratches
- diabetes mellitus
- corticosteroid treatment
- chemotherapy in patients with hematologic malignancy
- hematopoietic stem cell/solid organ transplantation
- tumor necrosis factor (TNF)-alpha inhibitor therapy
1st investigations to order
- skin lesion fungal culture
- skin lesion histopathology (Gomori methenamine silver, periodic acid-Schiff staining)
- erythrocyte sedimentation rate
- joint x-ray
- fungal culture of arthrocentesis synovial fluid
- sputum or bronchoalveolar lavage (BAL) fungal culture
- lumbar puncture for cerebrospinal fluid analysis
- cerebrospinal fluid (CSF) fungal culture
- fungal blood culture
Investigations to consider
- synovial tissue biopsy for fungal culture
- synovial tissue histopathology (Gomori methenamine silver, periodic acid-Schiff staining)
- bronchial biopsy fungal culture
- bronchial biopsy histopathology
- CT of chest
- serum itraconazole levels
- serum BUN
- serum creatinine
- serologic testing
- immunohistochemical staining
- polymerase chain reaction (PCR)
nonpregnant: extracutaneous mild/moderate disease
nonpregnant: extracutaneous severe/life-threatening disease
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