Sporotrichosis
Sporotrichosis is an infectious disease caused by the soil fungus *Sporothrix schenckii*, primarily affecting the skin. It is typically contracted through small cuts or punctures when handling contaminated materials, such as thorny plants, hay, or sphagnum moss. Although it can be inhaled in rare cases, sporotrichosis is not transmitted from person to person. The initial symptom is often a small, painless bump that may appear within one to twelve weeks post-exposure, which can progress into larger nodules and ulcerate over time. Most cases remain localized to the skin, but disseminated forms can occur, especially in individuals with weakened immune systems. Diagnosis involves a biopsy and laboratory culture of the fungus. Treatment commonly includes oral medications such as potassium iodide or itraconazole, while severe cases might require more aggressive therapies, including surgery. Preventive measures, such as wearing protective clothing while gardening or handling potentially contaminated materials, are recommended to minimize risk. With appropriate treatment, full recovery is generally achievable.
Sporotrichosis
- ANATOMY OR SYSTEM AFFECTED: Lymphatic system, skin
Definition
Sporotrichosis is an infectious disease caused by the soil fungus Sporothrix schenckii that usually affects the skin. Sporotrichosis is commonly acquired through cutaneous inoculation. In rare cases, it can be inhaled. It is not spread from person to person, but zoonotic transmission from infected animals (such as cats and horses) is possible.
Causes
S. schenckii is widely distributed in the natural environment and can be found on rose thorns and on twigs, and in sphagnum moss, hay, and soil. The fungus enters the skin through small cuts or punctures, and it spreads from the initial lesion along lymphatic channels. Hematogenous dissemination is rare.
Risk Factors
Persons handling thorny plants, sphagnum moss, or baled hay (such as farmers, nursery workers, landscapers, and gardeners) are at higher risk for the disease. Sporotrichosis resulting from inhalation has been documented in persons with severe chronic obstructive pulmonary disease. Immunosuppressive states and alcoholism predispose to disseminated disease. The disease is most common among adults and slightly more prevalent in males. Sporotrichosis in children may be more common in tropical regions.
Symptoms
The first symptom is a firm, pink to purple, usually painless skin nodule that resembles an insect bite. It may appear from one to twelve weeks after exposure to the fungus. Over time, the nodule may ulcerate and become chronic. The characteristic infection progresses proximally along lymphatic channels. In the vast majority of cases, disease is limited to the skin. Very rarely, the disease can infect the bones, joints, lungs, and brain. Widespread cutaneous lesions and involvement of multiple visceral organs (including eye, prostate, oral mucosa, paranasal sinuses, and larynx) predominantly occur in persons with compromised immune systems, such as those with human immunodeficiency virus infection, diabetes, alcoholism, or other disorders of the immune system.
Screening and Diagnosis
Diagnosis is based on a nodule biopsy and laboratory identification of the mold.
Treatment and Therapy
Skin sporotrichosis is traditionally treated with an oral, saturated potassium iodide solution (three times per day for three to six months until the skin lesions are completely healed). Oral itraconazole (200 milligrams once or twice daily) is the drug of choice for cutaneous and lymphocutaneous forms of the disease. It may also be used to treat bone and joint infections. For persons with severe disease or with pulmonary, brain, or disseminated infection, liposomal amphotericin B is generally recommended; once the person has stabilized, itraconazole can be used for step-down therapy. Infected bone or infected lung areas may need to be surgically removed.
Treating sporotrichosis may take several months or years. With treatment, full recovery can be expected. A spontaneous resolution of cutaneous sporotrichosis has been reported. Disseminated sporotrichosis is associated with significant morbidity and can be life-threatening for people with compromised immune systems.
Prevention and Outcomes
Preventive measures include wearing gloves, long sleeves, heavy boots, and other protective clothing when handling wires, rose bushes, hay bales, conifer (pine) seedlings, or other materials that may cause minor skin breaks. It is also advisable to avoid skin contact with sphagnum moss, which has been implicated as a source of the fungus in a number of outbreaks. When handling animals with skin lesions, the use of gloves minimizes the risk of zoonotic transmission.
Bibliography
Greenfield, Ronald A. “Sporotrichosis.” Medscape, 18 Dec. 2024, emedicine.medscape.com/article/228723-overview. Accessed 4 Feb. 2025.
Kauffman, Carol A. “Sporotrichosis.” Clinical Infectious Diseases 29 (1999): 231-236.
‗‗‗‗‗‗‗, et al. “Clinical Practice Guidelines for the Management of Sporotrichosis: 2007 Update by the Infectious Diseases Society of America.” Clinical Infectious Diseases 45 (2007): 1255-1265.
"Sporotrichosis Basics." Centers for Disease Control and Prevention (CDC), 24 Apr. 2024, www.cdc.gov/sporotrichosis/about/index.html. Accessed 4 Feb. 2025.