Fusarium infections of the skin

Fusarium species are ubiquitous and may be found in the soil, air and on pl ants. Fusarium species can cause mycotoxicosis in humans following ingestio n of food that has been colonized by the fungal organism. In humans, Fusari um species can also cause disease that is localized, focally invasive or di sseminated. The pathogen generally affects immunocompromised individuals wi th infection of immunocompetent persons being rarely reported. Localized in fection includes septic arthritis, endophthalmitis, osteomyelitis, cystitis and brain abscess. In these situations relatively good response may be exp ected following appropriate surgery and oral antifungal therapy. Disseminat ed infection occurs when two or more noncontiguous sites are involved. Over eighty cases have been reported, many of which had a hematologic malignanc y including neutropenia. The species most commonly involved include Fusariu m solani, Fusarium oxysporum, and Fusarium moniliforme (also termed F. vert icillioides). The diagnosis of Fusarium infection may be made on histopatho logy, gram stain, mycology, blood culture, or serology. Portals of entry of disseminated infection include the respiratory tract, the gastrointestinal tract, and cutaneous sites. The skin can be an important and an early clue to diagnosis since cutaneous lesions may be observed at an early stage of the disease and in about seve nty-five cases of disseminated Fusarium infection. Typical skin lesions may be painful red or violaceous nodules, the center of which often becomes ul cerated and covered by a black eschar. The multiple necrotizing lesions are often observed on the trunk and the extremities. Onychomycosis most common ly due to F. oxysporum or F. solani has been reported. The onychomycosis ma y be of several types: distal and lateral subungual (DLSO), white superfici al (WSO), and proximal subungual (PSO). In proximal subungual onychomycosis there may be associated leukonychia and/or periungual inflammation. Patien ts with Fusarium onychomycosis have been cured following therapy with itrac onazole, terbinafine, ciclopirox olamine lacquer, or topical antifungal age nt. In other instances nail avulsion plus antifungal therapy has been succe ssful. In patients with hematologic malignancy or bone marrow transplant, w ho may experience prolonged or severe neutropenia during the course of ther apy, the skin and nails should be carefully examined and consideration give n to treating potential infection sites that may serve as portals for syste mic dissemination. When disseminated Fusarium infection is present therapy with antifungal agents has generally been disappointing with the chances of a successful resolution being enhanced if the neutropenia can be corrected in a timely manner. Curr Opin Infect Dis 13:121-128. (C) 2000 Lippincott W illiams & Wilkins.