Sporotrichosis

Sporotrichosis is a chronic fungal disease that results from inoculation into the subcutaneous tissue through minor trauma. Plant nursery workers, florists, and gardeners can acquire it from roses, sphagnum moss, and other plants. Plague sporotrichosis is limited to the site of the infection, and lymphangitis sporotrichosis occurs when the infection spreads along proximal lymph channels. Spread beyond the extremity is rare. Osteoarticular, pulmonary, and other extracutaneous forms are likely to evolve from the lung.

Causes

Sporotrichosis is caused by the fungus, Sporothrix schenckii, which is found in soil, wood, sphagnum moss, and decaying vegetation throughout the world. The fungus usually enters through broken skin or through inhalation (pulmonary form).

Signs and symptoms

The first symptom is usually a small painless bump resembling an insect bite. It can be red, pink, or purple in color. The bump (nodule) usually appears on the finger, hand, or arm where the fungus first enters through a break on the skin. This is followed by one or more additional bumps or nodules which open and may resemble boils. Eventually lesions look like open sores (ulcerations) and are very slow to heal. The infection can spread to other areas of the body.

Diagnostic tests

Culture of S. schenckii in sputum, pus, or bone drainage confirms the diagnosis. Histologic identification is difficult. Despite pulmonary symptoms, few definitive abnormalities appear on a chest X-ray.

Treatment

The cutaneous lymphatic form of the disease usually responds to application of a saturated solution of potassium iodide, usually continued for 1 month after lesions heal. The extracutaneous form responds to I.V. amphotericin B but may require several weeks of treatment.

Prevention

Safer sex behavior can help prevent infection with HIV, the virus that causes AIDS. People with compromised immune systems should try to minimize exposure by taking measures like wearing thick gloves while gardening.