Sporotrichosis
Key points
- Sporotrichosis is a chronic skin infection, caused by a fungus which may become a widespread (disseminated, systemic) infection, particularly in people with weakened immune systems.
- Sporotrichosis is caused by the fungus Sporothrix schenckii, which is found in vegetation.
- Signs and tests A physical examination reveals the typical lesions.
- The skin infection is usually treated with potassium iodide (for example, SSKI) given by mouth 3 times per day or itraconazole by mouth.
Definition
Sporotrichosis is a chronic skin infection, caused by a fungus which may become a widespread (disseminated, systemic) infection, particularly in people with weakened immune systems.
Causes, incidence, and risk factors
Sporotrichosis is caused by the fungus Sporothrix schenckii, which is found in vegetation. Infection commonly occurs when the skin is broken while handling plant materials such as rosebushes, briars, or mulch-rich dirt.
Sporotrichosis can be an occupational disease (for farmers, horticulturists, rose gardeners, plant nursery workers). Widespread (disseminated) sporotrichosis can develop in immunocompromised people when they inhale spore-laden dust.
Symptoms include a small, painless, red lump that develops at the site of infection and ultimately develops into an ulcer. Lesions are often on the hands and forearm, as these areas are a common site of injury.
The organism follows the lymph flow causing small ulcers to appear in lines on the skin as the infection progresses up the arm (or leg). These lesions do not heal unless treated and may remain ulcerated for years.
Systemic sporotrichosis can cause lung and breathing problems, osteomyelitis, arthritis, and Meningitis.
Symptoms
- Small, painless, red lump that develops at site of a recent injury (up to 3 months following injury).
- A progressive line of ulcers leading away from the initial ulcer.
Signs and tests
A physical examination reveals the typical lesions. A culture of biopsied tissue that demonstrates Sporothrix schenckii confirms the diagnosis.
Treatment
The skin infection is usually treated with potassium iodide (for example, SSKI) given by mouth 3 times per day or itraconazole by mouth. Treatment is prolonged and continues 1 month after the skin lesions clear. Systemic or disseminated infection is often treated with Amphotericin B, or sometimes itraconazole.
Expectations (prognosis)
With treatment, full recovery can be expected. Disseminated sporotrichosis is more difficult to treat and requires chemotherapeutic agents. Disseminated sporotrichosis can be life-threatening for immunocompromised people.
Complications
In people with a normal immune system:
- Secondary skin infections
- Discomfort
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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