Sporotrichosis is a long-term (chronic) skin infection due to a certain fungus.
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 a job-related disease (for farmers, horticulturists, rose gardeners, and plant nursery workers). Widespread (disseminated) sporotrichosis can develop in people with compromised immune systems when they inhale dust filled with spores.
Symptoms include a small, painless, red lump that develops at the site of infection and eventually turns into an ulcer. The lump may develop up to 3 months after an injury.
Sores are often on the hands and forearm, because these areas are common injury sites.
The fungus follows lymphatic channels in the body. Small ulcers appear in lines on the skin as the infection goes up an arm or leg. These sores do not heal unless they are treated and may remain for years. The nodules may drain small amounts of pus from time to time.
Body-wide (systemic) sporotrichosis can cause lung and breathing problems, bone infection, arthritis, and infection of the nervous system.
Signs and tests
A physical examination reveals the typical sores. In some cases, a small sample of affected tissue is removed, examined under a microscope and cultured to identify the fungus.
The skin infection is usually treated with an antifungal medicine called itraconazole. It is taken by mouth and continued for 2 to 4 weeks after the skin lesions have cleared. You may have to take the medicine for 3 to 6 months.
Fluconazole is used in patients who do not respond to itraconazole. Systemic or disseminated infection is often treated with amphotericin B, or sometimes itraconazole. Therapy for systemic disease can last up to 12 months.
With treatment, full recovery can be expected. Disseminated sporotrichosis is more difficult to treat and requires chemotherapy drugs. Disseminated sporotrichosis can be life-threatening for people with a compromised immune system.
In people with a normal immune system:
- Secondary skin infections (such as staph or strep)
In people who are immunosuppressed:
Calling your health care provider
Call for an appointment with your health care provider if you develop persistent skin lumps or skin ulcers. If you know that you have been exposed to vegetation, mention this to your health care provider.
People with compromised immune systems should try to minimize skin injury by taking measures like wearing thick gloves while gardening.
Kauffman CA. Sporotrichosis. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 358.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Jatin M. Vyas, PHD, MD, Assistant Professor in Medicine, Harvard Medical School, Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.