Sporotrichosis refractory to conventional treatment: therapeutic success with potassium iodide

Abstract

Sporotrichosis is a subcutaneous mycosis caused by dimorphic fungi of the genus Sporothrix. The authors report a case of fixed cutaneous sporotrichosis with therapeutic failure after 18 months of itraconazole and terbinafine associated with cryosurgery. The patient was cured after the introduction of saturated potassium iodide solution. Sporothrix brasiliensis was the identified species, presenting a susceptibility profile to itraconazole and terbinafine. This fact suggests that therapeutic failure is probably related to the host-fungus interaction rather than drug resistance. It is possible that the immunomodulatory action of the saturated potassium iodide solution may have played an important role in curing this patient.

Keywords: Cryosurgery; Itraconazole; Potassium iodide; Sporothrix; Sporotrichosis.

Figure 1

Infiltrated plaque with central ulceration surrounded by multiple satellite papules of 75 days evolution.

Figure 2

Sporothrix brasiliensis – left, colony macromorphology in the filamentous phase in potato dextrose agar (PDA), after 14 days of incubation at 30 °C. On the right, microscopy of the filamentous phase, stained by cotton blue with lactophenol (× 400).* The experiments of this work were carried out at the Mycology Laboratory of the National Institute of Infectious Diseases Evandro Chagas INI - Fiocruz/RJ.

Figure 3

Infiltrated plaque with central sero-hematic crust after 18 months of treatment. Eleven months with itraconazole followed by seven months of terbinafine, combined with 11 sessions of cryosurgery at monthly intervals.

Figure 4

Lesion completely healed after 20 months of evolution and two months of treatment with saturated solution of potassium iodide.