April 2006

This 4-year-old boy (figure 1) presented to the office with a history of crusting and drainage of the surface of the nose for several weeks. His parents said the lesion initially looked like a mosquito bite and then progressed to its appearance at the time of presentation.

Previously, a simple wound culture for bacteria was negative. He had been treated with antibiotics and prednisone with little or no improvement. The lesion has continued to spread slowly. He lives on a farm in Indiana. His family owns a few livestock, chickens and two cats.

What is the diagnosis?

Answer

The child’s physician sent fresh tissue from a biopsy for culture and grew Sporothrix schenckii.

S. schenckii is a dimorphic fungus, which grows as an oval or cigar-shaped yeast 98.6°F. It can be found in soil, hay, straw, thorny plants (especially roses), sphagnum moss and decaying vegetation.

Cutaneous sporotrichosis is the most common manifestation of an infection with S. schenckii. Inoculation occurs in the presence of a minor break in the skin. After one to 12 weeks, a painless nodule, which is typically red or violaceous, appears at the site of the inoculation. More nodules develop, and these tend to open, ulcerate and drain. Pulmonary and disseminated forms of sporotrichosis can be seen in immunocompromised patients.

Differential diagnoses

Differential diagnoses for this condition should include herpes, mycetoma, blastomycosis, chromoblastomycosis, mycobacterium infections and discoid lupus.

Our patient was treated for three months with saturated solution of potassium iodide. He healed with scarring (figure 2). Itraconazole is approved for treatment of cutaneous and lymphocutaneous sporotrichosis in adults; however, the 2003 Red Book states: “Although there are no controlled trials to document the efficacy of itraconazole in pediatric patients, most experts consider itraconazole the preferred treatment”.

Immunocompromised patients with disseminated sporotrichosis often require treatment with amphotericin B.

Recommendations for prevention include wearing gloves and long sleeves when working with materials where the fungus can be found.

For more information:

• Umemoto N, Demitus T, Osawa M, et al. Sporortrichosis in a husband and wife. J Dermatol. 2005;32:569-573.
• Wroblewska M, Swoboda-Kopec E, Kawecki D, et al. Infection by a dimorphic fungus Sporothrix schenckii in an immunocompromised patient. Infection. 2005;33:289-291.
• Civila ES, Bonasse J, Conti-Diaz IA, et al. Importance of the direct fresh examination in the diagnosis of cutaneous sporotrichosis. Int J Dermatol. 2004;43:808-810.
• Coles FB, Schulchat A, Hibbs JR, et al: A multistate outbreak of sporotrichosis associated with sphagnum moss. Am J of Epidemiol 1992;136:475-487.