Sporotrichosis

                

Sporotrichosis is an infection caused by a fungus called Sporothrix schenckii. The fungus lives throughout the world in soil, plants, and decaying vegetation. Cutaneous (skin) infection is the most common form of infection, although pulmonary infection can occur if a person inhales the microscopic, airborne fungal spores. Most cases of sporotrichosis are sporadic and are associated with minor skin trauma like cuts and scrapes; however, outbreaks have been linked to activities that involve handling contaminated vegetation such as moss, hay, or wood. 

This fungal disease usually affects the skin, although other rare forms can affect the lungs, joints, bones, and even the brain. Because roses can spread the disease, it is one of a few diseases referred to as rose-thorn or rose-gardeners' disease.  

Because S. schenckii is naturally found in soil, hay, sphagnum moss, and plants, it usually affects farmers, gardeners, and agricultural workers. It enters through small cuts and abrasions in the skin to cause the infection. In case of sporotrichosis affecting the lungs, the fungal spores enter through the respiratory pathways. Sporotrichosis can also be acquired from handling cats with the disease; it is an occupational hazard for veterinarians. 

Sporotrichosis progresses slowly - the first symptoms may appear 1 to 12 weeks (average 3 weeks) after the initial exposure to the fungus. Serious complications can also develop in patients who have a compromised immune system. 

SYMPTOMS: 

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. 

When S. schenckii spores are inhaled. Symptoms of pulmonary sporotrichosis include productive coughing, nodules and cavitations of the lungs, fibrosis, and swollen hilar lymph nodes. Patients with this form of sporotrichosis are susceptible to developing tuberculosis and pneumonia 

When the infection spreads from the primary site to secondary sites in the body, the disease develops into a rare and critical form called disseminated sporotrichosis. The infection can spread to joints and bones (called osteoarticular sporotrichosis) as well as the central nervous system and the brain (called sporotrichosis meningitis). 

The symptoms of disseminated sporotrichosis include weight loss, anorexia, and appearance of bony lesions. 

DIAGNOSIS: 

Sporotrichosis is typically diagnosed when your doctor obtains a swab or a biopsy of the infected site and sends the sample to a laboratory for a fungal culture. Serological tests are not always useful in the diagnosis of sporotrichosis due to limitations in sensitivity and specificity. 

TREATMENT: 

Treatment of sporotrichosis depends on the severity and location of the disease. The following are treatment options for this condition:  

• Saturated potassium iodide solution  

Although its mechanism is unknown, application of potassium iodide in droplet form can cure cutaneous sporotrichosis. This usually requires 3 to 6 months of treatment. 

• Itraconazole (Sporanox) and fluconazole 

These are antifungal drugs. Itraconazole is currently the drug of choice and is significantly more effective than fluconazole. Fluconazole should be reserved for patients who cannot tolerate itraconazole. 

• Amphotericin B 

This antifungal medication is delivered intravenously. Many patients, however, cannot tolerate Amphotericin B due to its potential side effects of fever, nausea, and vomiting. 

Lipid formulations of amphotericin B are usually recommended instead of amphotericin B deoxycholate because of a better adverse-effect profile. Amphotericin B can be used for severe infection during pregnancy. For children with disseminated or severe disease, amphotericin B deoxycholate can be used initially, followed by itraconazole. In case of sporotrichosis meningitis, the patient may be given a combination of Amphotericin B and 5-fluorocytosine/Flucytosine. 

• Newer triazoles 

Several studies have shown that posaconazole has in vitro activity similar to that of amphotericin B and itraconazole; therefore, it shows promise as an alternative therapy. However, voriconazole susceptibility varies. Because the correlation between in vitro data and clinical response has not been demonstrated, there is insufficient evidence to recommend either posaconazole or voriconazole for treatment of sporotrichosis at this time.  

• Surgery 

In cases of bone infection and cavitatory nodules in the lungs, surgery may be necessary. 

PREVENTION 

The most important step in preventing sporotrichosis is preventing mold spores from entering the skin. 

• People who work with roses, hay, or sphagnum moss should cover any scratches or breaks in their skin. 
• They should wear heavy boots and gloves to prevent puncture wounds. 

• People with a suppressed immune system should be exceptionally careful to avoid any contact with rose thorns or soil and moss used for gardening or farm use.