Potassium Iodide Remains the Most Effective Therapy for Cutaneous Sporotrichosis

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Potassium iodide remains the most effective therapy for cutaneous sporotrichosis

K Sandhu and S Gupta Sporotrichosis is a subcutaneous failed to respond to an adequate fungal infection caused by the course of itraconazole yet res- Department of Dermatology, dimorphic fungus Sporothrix ponded dramatically to treat- Venereology and Leprology, schenckii. Itraconazole has lar- ment with saturated solution Postgraduate Institute of Medical gely replaced older therapies, but of potassium iodide (SSKI). Education and Research, Chandigarh, we present a case of lympho- (J Dermatol Treat (2003) 14: 200– India cutaneous sporotrichosis that 202)

Received 26th June 2002 Keywords: Cutaneous sporotrichosis — Itraconazole — Potassium iodide Accepted 18th December 2002

Sporotrichosis is a subcutaneous fungal infection caused crust. The lesion over the pinna was more infiltrated, by the dimorphic fungus Sporothrix schenckii. Sponta- hyperkeratotic and less moist. There was no regional neous resolution is rare and infection tends to run a lymphadenopathy and no palpable lymphatic cord. chronic course, treatment therefore being necessary. Histopathology from both the lesions showed mildly Infection commonly involves the skin and subcutaneous hyperplastic epithelium with a moderate degree of mixed tissues, but rarely lungs, bone, joints, and other organs inflammatory infiltrate along with foci of granulation can also be involved.1 Itraconazole has largely replaced tissue with giant cells in the adjoining dermis. A PAS older therapies (such as saturated solution of potassium stain revealed budding spores with a hyper-dense iodide (SSKI), amphotericin-B) with its 90–100% periphery. These changes were consistent with the response rate in patients with cutaneous as well as diagnosis of sporotrichosis. Culture from the lesions systemic sporotrichosis.2 However, we came across a showed growth of S. schenckii. case of lymphocutaneous sporotrichosis that failed to The patient was started on itraconazole 200 mg twice respond to an adequate course of itraconazole. daily orally. Even after 12 weeks of therapy, no signi- ficant regression of the lesions was noted so the patient was started on SSKI (initially five drops tid, gradually CASE REPORT increasing to 40 drops tid). He responded dramatically with over 90% regression of the lesions within a period A 44-year-old man presented with asymptomatic of 5 weeks. The patient continued on SSKI for one more crusted plaque lesions on the right cheek and right month after complete clearance of lesion. The patient external ear of 2 years duration. There was no history tolerated the drug well and had slight gastrointestinal of trauma prior to the onset of the lesions. The lesion upset and headache. There has been no relapse after a started as a small papule on the right preauricular follow-up period of more than 5 months. region, which increased in size and over a period of time spread to involve the right pinna. There was a history of serous discharge and bleeding from the lesion. On examination two well-defined erythematous plaques DISCUSSION measuring 864 cm and 563 cm were present over the right cheek and pinna – but were separate from each Treatment options for fixed cutaneous and other. The surface of the lesions was covered with lymphocutaneous-type sporotrichosis include SSKI, itraconazole, fluconazole, ketoconazole, terbinafine and Correspondence: localized hyperthermia.3 Amphotericin-B though effect- Somesh Gupta MD, Assistant Professor, Department of Dermatology, ive is not used because of its toxicity. There are no Venereology and Leprology, PGIMER, Sector 12, Chandigarh, India. Tel z91 172 747585 (ext 6561, 6967); Fax z91 172 744401, randomized, blinded and controlled trials for the 745078; E-mail: [email protected] treatment of sporotrichosis. K Sandhu and S Gupta Cutaneous sporotrichosis clearing with KI 201

with doses ranging from 100 to 400 mg/day for a period varying from 15 days to 6 months.4–6 Subsequently, itraconazole has proven efficacious in the treatment of patients with systemic and osteoarticular sporotrichosis.7 De Beurmann initially used iodides in the early 1900s as an effective treatment for cutaneous sporotrichosis,8 and indeed SSKI was a standard treatment for lymphocutaneous sporotrichosis until recently. The mechanism by which iodides act against S.schenkii is still not known. It is not clear whether KI is active against fungi because of its fungicidal nature or it acts by enhancing the host’s immunological or non- 8 Figure 1 immunological defence mechanisms. SSKI does not Crusted plaque lesions over the right preauricular region and pinna. directly kill or inhibit S. schenkii as it has been shown that S. schenckii grows well when plated with 10% saturated solution of KI.9 KI does not appear to increase monocyte or neutrophil killing of S. schenckii.10 Its therapeutic effect in inflammatory dermatoses is thought to be due to inhibition of neutrophil chemotaxis in the peripheral blood.11 Miyachi and Niwa found that both KI and dapsone suppress the ability of the neutrophil to generate the toxic intermediates hydrogen peroxide and hydroxyl radicals in vitro.12 KI might have some direct effect on the fungus as an ultrastructure examination of S. schenckii exposed to iodine-potassium iodine solution showed inhibition of the germination of cells and rapid destruction of fungal cells.13 It was therefore proposed that KI may be converted into iodine in vivo by myeloperoxidase – a hydrogen peroxide system of polymorphonuclear cells – and thereby could exert a Figure 2 fungicidal effect.13 Almost complete clearance of lesions after 5 weeks of SSKI therapy. KI is still the most effective, cheap, easily available therapeutic modality for sporotrichosis. The problem Recently, itraconazole in a dose of 100–200 mg/day associated with its use includes poor tolerability and has been recommended as first-line therapy for uncom- compliance. Although it is not useful in patients plicated cutaneous sporotrichosis based on a few uncon- with extensive and systemic disease, its century- trolled open trials.3,4–6 Itraconazole has been found to proven effectiveness in the management of limited be superior to other azoles as it has greater activity disease should not be ignored on the basis of a against S. schenckii. Initial studies with itraconazole few non-randomized clinical trials with newer drugs. were in patients with cutaneous and lymphocutaneous We recommend larger, randomized, comparative trials sporotrichosis. Up to a 100% response rate was reported, with itraconazole before the guidelines are laid down.

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