Sporotrichosis is a chronic systemic fungal disease, acquired usually by traumatic implantation and localized to cutaneous lymphatic tissues, or rarely by the respiratory route with dissemination throughout the body.
History of Sporotrichosis.
From & patient at Johns Hopkins Hospital, in 1896 Schenck isolated a fungus that was identified by E. F. Smith as Sporotrichum; it was called Sporotrichum schenckii by Hektoen and Perkins in 1900. A great number of cases were seen subsequently in France, and more than 2800 cases in a single epidemic in the gold mines of South Africa.
Etiology of Sporotrichosis.
Sporotrichum schenckii, a dimorphic fungus, is occasionally observed in tissues as round to cigar-shaped yeastlike forms. On Sabouraud glucose medium at room temperature, a white, cottony, aerial mycelium appears that in three to seven days becomes wrinkled and changes in color from cream to black. Microscopically, branching, septate hyphae are seen, 2 /u, in width, bearing directly or on lateral branches ovoid to spherical bodies (conidia) measuring 2 to 4 by 2 to 6 /jl in diameter. Mice are susceptible to experimental infection. Delayed cutaneous hypersensitivity and agglutinogen antigens have been demonstrated.
Epidemiology of Sporotrichosis
The disease is worldwide in distribution; it has appeared epidemically in South Africa and in localized outbreaks in Mexico and Florida. It is more common in the male. It frequently affects laborers, farmers, and florists and is considered a true occupational disease. The fungus exists in its saprophytic form in soil, peat moss, decaying vegetation, and on thorns. In the cutaneous lymphatic forms, infection results from accidental implantation into the skin. In disseminated forms, the mode of entry is probably respiratory. Spontaneous sporotrichosis has been reported in dogs, horses, mules, cats, and other animals, and human disease has resulted from animal contact. Direct transfer from man to man is not known to occur.
Pathology of Sporotrichosis .
The histopathologic reaction to S. schenckii is varied, frequently acute and suppurative, but also subacute or chronic. In some instances granulomas are seen with epithelioid and giant cells either diffusely distributed or localized in a typical tubercle. Fungi may be seen more readily after staining with a modified Schiff-MacManus technique.
Clinical Forms of Sporotrichosis.
Cutaneous Lymphatic Form. The earliest lesion is a pustule, papule, or nodule of the skin appearing characteristically on a finger and at a site where the patient may recall an earlier, seemingly insignificant scratch or prick. The nodule enlarges, becomes ?ed to violaceous, and is followed by a chain of subcutaneous nodules along regional lymphatics. These at first freely movable nodules may become attached to the skin, and may ulcerate and drain a thin gray to yellow pus. Streaking and pain characteristic of acute lymphangitis are not present. Generalized symptoms are rare.
Other Forms of Sporotrichosis.
Other forms may appear secondary to the cutaneous lymphatic lesion either by direct extension to contiguous subcutaneous tissue, bone, and joint or by hematogenous spread to distant sites. Sometimes the original site of infection is inapparent, and the disease presents as a septic arthritis or osteomyelitis. Less fre-frequently, lenore may be involvement of the eye,lungs, gastrointestinal tract, central nervous system, or skin.
In disseminated disease, systemic symptoms of fever, weight loss, inanition, malaise, pain at sites of lesion, anemia, and leukocytosis are commonly present. Disease limited to the lungs or localized there suggests that there is a respiratory form acquired by inhalation of the fungus. Too few cases have thus far been reported to characterize this form at present.
Diagnosis of Sporotrichosis.
Although the diagnosis may seem readily apparent in the cutaneous lymphatic form of disease, the clinical impression is confirmed by the culture and identification of the fungus. Agglutination or complement-fixation serologic and skin tests may be helpful, but are not generally available.Cutaneous lymphatic sporotrichosis must be distinguished from tularemia, pyoderma of bacterial origin, and other fungal infections. Disseminated disease resembles tuberculosis, staphylococcal osteomyelitis, or neoplastic disease.
Natural Treatment of Sporotrichosis.
The cutaneous lymphatic form of disease responds slowly but progressively to the oral administration of iodides in the form of a saturated solution (1 gram per milliliter) of potassium iodide given in dosage of 2 ml. four times daily. Treatment should be prolonged one to two months beyond the time of apparent healing.Disseminated disease, especially of bone and joint is frequently resistant to iodide therapy. Dramatic improvement has been seen in a few treated -.with amphotericin B.