Introduction
Background
Sporotrichosis is a subacute or chronic infection caused by the soil fungus Sporothrix schenckii. Although only one species of Sporothrix was classically identified, modern phylogenetic studies suggest the geographic distribution of multiple distinct Sporothrix species.1 The characteristic infection involves suppurating subcutaneous nodules that progress proximally along lymphatic channels (lymphocutaneous sporotrichosis). Primary pulmonary infection (pulmonary sporotrichosis) is rare, as is direct inoculation into tendons, bursae, or joints. Osteoarticular sporotrichosis is caused by direct inoculation or hematogenous seeding. In rare cases, disseminated S schenckii infection (disseminated sporotrichosis) occurs, characterized by disseminated cutaneous lesions and involvement of multiple visceral organs; this occurs most commonly in persons with AIDS.
Pathophysiology
Infection with the dimorphic soil fungus S schenckii is usually acquired through cutaneous inoculation.
Photomicrograph that shows the conidiophores and conidia of the fungus Sporothrix schenckii. Photo from CDC Public Health Image Library.
{{mediacaption:1466409_0}}The initial reddish, necrotic, nodular papule of cutaneous sporotrichosis generally appears 1-10 weeks after a penetrating skin injury. The lesion is a suppurating granuloma that consists of histiocytes and giant cells, with neutrophils that accumulate in the center and that are surrounded by lymphocytes and plasma cells.
The S schenckii infection spreads from the initial lesion along lymphatic channels, forming the chain of indolent nodular and ulcerating lesions typical of lymphocutaneous sporotrichosis.
Other tissues are involved by direct extension and, less often, by hematogenous dissemination. The most common extracutaneous infection sites are in the bones, joints, tendon sheaths, and bursae. Hematogenous dissemination—particularly in immunocompromised hosts—results in widely disseminated cutaneous and visceral infection, including meningitis.
A rare form of sporotrichosis appears to result from inhalation of the organism. This form is characterized by a chronic cavitary pneumonia that is clinically and radiographically indistinguishable from tuberculosis and histoplasmosis. This form of sporotrichosis is most common in individuals with severe underlying chronic obstructive pulmonary disease (COPD). Sporotrichal infection of the larynx and paranasal sinuses has also been described.
Frequency
United States
The incidence of sporotrichosis is not precisely known but is estimated at 1-2 cases per million population. An estimated 200-250 cases occur per year.
International
Sporotrichosis occurs worldwide, with focal areas of hyperendemicity. The global incidence is unknown. In the highlands of Peru, the incidence of sporotrichosis is approximately 1 case per 1000 people.2
Mortality/Morbidity
- Spontaneous resolution of cutaneous and lymphocutaneous forms of sporotrichosis has been documented.
- The prognosis is excellent for complete recovery after therapy, although the response to therapy may vary.
- Pulmonary sporotrichosis may contribute to declining pulmonary function in patients with COPD.
- Osteoarticular sporotrichosis may result in significant morbidity in the form of chronic osteomyelitis and arthritis with significant loss of joint function and deformity.
- Disseminated sporotrichosis is associated with significant morbidity and, possibly, mortality in immunocompromised hosts.
Race
Sporotrichosis has no known racial predilection.
Sex
Sporotrichosis is slightly more common in males than in females, presumably due to an increased exposure risk rather than to a difference in susceptibility.
Age
In developed nations, sporotrichosis is most common among adults. However, in tropical regions and in areas of hyperendemicity, sporotrichosis may be more common in children and adolescents. For more on pediatric sporotrichosis, see the article Sporotrichosis in eMedicine’s Pediatric: General Medicine volume.
Clinical
History
- Cutaneous and lymphocutaneous sporotrichosis: The primary lesion develops at the site of cutaneous inoculation, typically in the distal upper extremities. Patients with these forms are typically afebrile and not systemically ill. The lesions usually cause minimal pain. Many affected patients have received one or more courses of antibacterial therapy without benefit.3,4
- Pulmonary sporotrichosis: Patients with this form of sporotrichosis usually have severe underlying COPD and present with subacute or chronic pneumonia.5 The presenting symptoms of pulmonary sporotrichosis are not specific but typically include increased cough and few constitutional symptoms.
- Osteoarticular sporotrichosis
- Sporotrichosis may present as a chronic arthritis that is often confused with rheumatoid arthritis or other chronic inflammatory arthritis. In many cases, the osteoarticular sporotrichosis persists for 10 or more years until destruction of adjacent bone or the development of draining fistulae encourages efforts to establish the microbial etiology of the chronic osteomyelitis with culture. Cutaneous or lymphocutaneous lesions are not prominent in these patients.
- The process generally begins as a monoarticular arthritis, but other joints may become involved successively. The patient usually has pain upon motion, but not the severe limitation characteristic of bacterial arthritis. Systemic illness is usually absent. Functional impairment due to osteoarticular sporotrichosis may become severe.
- Disseminated sporotrichosis: In rare cases, sporotrichosis involves other organs, including the eye, the prostate, the oral mucosa, the paranasal sinuses, and the larynx. In such patients, the clinical manifestations depend on the organs involved. Central nervous system and meningeal involvement are more common in the AIDS era, but it remains rare. In some cases, the only symptom is subtle changes in mental status. Patients with AIDS who develop disseminated sporotrichosis may present with cutaneous dissemination, which manifests as nodules, ulcers, or both, with or without evidence of visceral involvement and meningitis.
Physical
- Cutaneous or lymphocutaneous sporotrichosis: An initial papule or nodule forms at the site of cutaneous inoculation, usually 1-10 weeks after inoculation. The initial small nodule enlarges, reddens, becomes pustular, and ulcerates. In the lymphocutaneous form, an ascending chain of nodules develops along skin lymphatic channels. Older distal lesions ulcerate and drain, while more proximal lesions appear as nodules and undergo the same evolution.
Lymphocutaneous sporotrichosis.
Lymphocutaneous sporotrichosis.
Lymphocutaneous sporotrichosis.
- Pulmonary sporotrichosis: The physical examination findings in patients with pulmonary sporotrichosis are typically dominated by their underlying COPD. No physical findings are specific for pulmonary sporotrichosis.
- Osteoarticular sporotrichosis: Patients typically have a subacute or chronic inflammatory monoarticular arthritis. The involved joint has an effusion, may be warm, and may have overlying erythema. Draining sinus tracts that complicate adjacent osteomyelitis may be apparent.
- Disseminated sporotrichosis: Physical findings vary depending on the site of involvement. Cutaneous dissemination may appear as subcutaneous mass lesions, diffuse purplish papules and nodules, or disseminated ulcerative lesions.
This photo depicts cutaneous disseminated sporotrichosis in a patient with AIDS before and after therapy. (Courtesy of Leonard N. Slater, MD)
Causes
- Sporotrichosis is caused by infection with S schenckii, a fungus widely distributed in the natural environment. It grows on plant debris in soil and on the bark of trees, shrubs, and garden plants.
- Splinters, thorns, or woody fragments of plants usually provide the penetrating trauma that introduces the fungal conidia into the human host; however, contact with any plant or plant product (eg, sphagnum peat moss, mulch, hay, timber) that causes minor skin trauma may initiate infection.
- Activities associated with the acquisition of sporotrichosis include gardening, landscaping, farming, berry-picking, horticulture, and carpentry.
- Zoonotic transmission can occur from infected animals (eg, cats, horses with extensive skin lesions) to their animal handlers.
- Both pulmonary and disseminated sporotrichosis are more common in persons with a history of alcoholism.
- Immunosuppressing states such as HIV infections and AIDS predispose to disseminated cutaneous sporotrichosis and hematogenously disseminated sporotrichosis, including sporotrichotic meningitis.6 This clinical observation, combined with studies in animal models, indicates the importance of cell-mediated immunity in the host defense against sporotrichosis.
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| References |
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References
Marimon R, Gene J, Cano J, et al. Molecular phylogeny of Sporothrix schenckii. J Clin Microbiol. Sep 2006;44(9):3251-6. [Medline].
Pappas PG, Tellez I, Deep AE, et al. Sporotrichosis in Peru: description of an area of hyperendemicity. Clin Infect Dis. Jan 2000;30(1):65-70. [Medline].
Kauffman CA. Sporotrichosis. Clin Infect Dis. Aug 1999;29(2):231-6; quiz 237. [Medline].
Winn RE. A contemporary view of sporotrichosis. Curr Top Med Mycol. 1995;6:73-94. [Medline].
Ramirez J, Byrd RP, Roy TM. Chronic cavitary pulmonary sporotrichosis: efficacy of oral itraconazole. J Ky Med Assoc. Mar 1998;96(3):103-5. [Medline].
Silva-Vergara ML, Maneira FR, De Oliveira RM, et al. Multifocal sporotrichosis with meningeal involvement in a patient with AIDS. Med Mycol. Mar 2005;43(2):187-90. [Medline].
Kauffman CA, Pappas PG, McKinsey DS, et al. Treatment of lymphocutaneous and visceral sporotrichosis with fluconazole. Clin Infect Dis. Jan 1996;22(1):46-50. [Medline].
Sharkey-Mathis PK, Kauffman CA, Graybill JR, et al. Treatment of sporotrichosis with itraconazole. NIAID Mycoses Study Group. Am J Med. Sep 1993;95(3):279-85. [Medline].
Chapman SW, Pappas P, Kauffmann C, et al. Comparative evaluation of the efficacy and safety of two doses of terbinafine (500 and 1000 mg day(-1)) in the treatment of cutaneous or lymphocutaneous sporotrichosis. Mycoses. Feb 2004;47(1-2):62-8. [Medline].
[Guideline] Kauffman CA, Bustamante B, Chapman SW, et al. Clinical practice guidelines for the management of sporotrichosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis. Nov 15 2007;45(10):1255-65. [Medline]. [Full Text].
Lyon GM, Zurita S, Casquero J, et al. Population-based surveillance and a case-control study of risk factors for endemic lymphocutaneous sporotrichosis in Peru. Clin Infect Dis. Jan 1 2003;36(1):34-9. [Medline].
Prentice AG, Glasmacher A. Making sense of itraconazole pharmacokinetics. J Antimicrob Chemother. Sep 2005;56 Suppl 1:i17-i22. [Medline].
Smego RA Jr, Castiglia M, Asperilla MO. Lymphocutaneous syndrome. A review of non-sporothrix causes. Medicine (Baltimore). Jan 1999;78(1):38-63. [Medline].
Further Reading
Keywords
sporotrichosis, Sporothrix schenckii, Schenck disease, Schenck’s disease, lymphocutaneous sporotrichosis, osteoarticular sporotrichosis, subacute sporotrichosis, chronic sporotrichosis, cutaneous sporotrichosis, pulmonary sporotrichosis, disseminated sporotrichosis, S schenckii, Sporothrix schenckii infection, S schenckii infection, Beurmann disease, Beurmann's disease, rose gardener's disease, rose thorn disease, peat moss disease, rose gardeners' disease, drunken rose gardener's disease, sporotrichotic meningitis, sporotrichotic arthritis, sporotrichal osteomyelitis
