A 46-Year-Old with Evolving Sores on Her Hand and Arm

Differential Diagnosis

• Rocky Mountain spotted fever
• Sporotrichosis
• Mycetoma
• Melioidosis

Diagnosis

The correct diagnosis is sporotrichosis, a disease caused by the dimorphic fungus Sporothrix schenckii, found worldwide but more commonly in tropical and subtropical climates. The organism resides in decaying vegetation, plants, and soil. Cutaneous infection usually results from traumatic inoculation. Sporotrichosis is the most common and least severe of the deep mycoses.

Learnings/What to Look for

• The lesions of sporotrichosis may present in three different patterns:
  • Lymphocutaneous or sporotrichoid pattern—as seen above, 75% of cases
  • Fixed cutaneous—no lymphatic dissemination; may be more likely to develop in patients previously sensitized to S schenckii
  • Disseminated cutaneous—occurs with systemic involvement, is rare and usually in the context of severe immunosuppressed states
• Thorny plants, such as barberry and rose bushes, are the most common source of cutaneous inoculation of sporotrichosis. Other plant exposures include sphagnum moss, straw, hay, soil, and mine timbers
• Occupational exposures include farmers, florists, gardeners, and forestry workers

Pearls for Urgent Care Management

• Untreated cutaneous sporotrichosis usually waxes and wanes over months to years without systemic manifestations
• Antifungal treatment is the standard of care
• Topical heat to lesions may be beneficial in strains that cause cutaneous or lymphocutaneous sporotrichosis

Acknowledgment: Image and case provided by VisualDx (www.VisualDx.com/JUCM).