Sporotrichosis is a skin infection caused by a fungus found primarily in vegetation. Sporotrichosis is one of the most common deep fungal infections of the skin, but it is also the least serious. This chronic fungal infection will appear at the sight of an insignificant wound, such as a cut or scrape, often on the hand or forearm. A small, red, painless nodule will appear at the sight of infection. About 20% of the time the nodule stays fixed and may heal and disappear, or progress into an ulcerated lesion. Usually however the fungus spreads in a line following the draining lymphatic channels forming nodules on the skin along the way.
Sporotrichosis is caused by the dimorphic (two forms) fungus, Sporothrix schenckii. This fungus dwells in vegetation typically found in warmer climates. It is found in Japan, North and South America (Mexico, Brazil, Uruguay, Peru, and Columbia.) Exposure to Sporothrix schenckii is largely occupational and hobby related. Occupations such as forestry, mining and gardening are at a higher risk for developing this infection.
Two main types of sporotrichosis exist, fixed and disseminated. Fixed sporotrichosis is isolated to the skin lesions mentioned above. Disseminated sporotrichosis begins as skin lesions and will progress into a systemic disease. Patients with diabetes mellitus, hematologic malignancies (leukemia), AIDS, chronic alcoholism or on oral prednisone therapy are at higher risk of developing disseminated sporotrichosis. The nodules will become ulcerated (open) and the disease will spread throughout the body. Arthritis is the most common symptom, but involvement of the gastrointestinal system, central nervous system and pulmonary system have been noted.
The diagnosis of sporotrichosis can be made by clinically by a physician, but usually a sample of the pus from the nodules will be collected and cultured to make a firm diagnosis. A full thickness skin biopsy can also be performed to aid in the diagnosis.
This fungal infection can be treated with antifungal medicines. Fixed sporotrichosis is treated with potassium iodide for 1 month or itraconazole for 2-4 weeks but can be used for up to 6 months. Disseminated sporotrichosis is treated with a higher dose of itraconazole for 6 months or amphotericin B may also be used.
Back to Index
The medical information provided in this site is for educational purposes only and is the property of the American Osteopathic College of Dermatology. It is not intended nor implied to be a substitute for professional medical advice and shall not create a physician - patient relationship. If you have a specific question or concern about a skin lesion or disease, please consult a dermatologist. Any use, re-creation, dissemination, forwarding or copying of this information is strictly prohibited unless expressed written permission is given by the American Osteopathic College of Dermatology.