Cellulitis in a Patient with Leukemia

Diagnosis: Disseminated Fusarium species infection.

Isolates from culture of the punch biopsy specimen obtained from the patient's lesions (figures 1 and 2) revealed Fusarium species on lactophenol blue stain, with canoe-shaped, septate macroconidia (figure 3) [1]. Fusarium species are ubiquitous in the environment. They may cause endopthalmitis, cellulitis, onchomycosis, osteomyelitis, sinusitis, or brain abscesses in immunocompetent individuals and have recently been implicated in an outbreak of keratitis among contact lens wearers [1–3]. For unknown reasons, soft contact lens wearers who used certain contact lens solutions appear to have been most affected. Of interest, ocular trauma did not appear to be a risk factor for infection [3]. In immunocompromised hosts, not only cellulitis but also disseminated infection with pneumonitis and bacteremia has been reported [1, 2].

Figure 1

The patient's foot on hospital day 9

Figure 2

The patient's hand after evolution of the target lesion on hospital day 9.

Figure 3

Lactophenol blue stain of tissue culture sample reveals Fusarium species with branching septate hyphae (thin black arrow) and canoe-shaped, septate macroconidia (thick black arrow).

Fusariosis has been reported to be a complication in 0.06% of cases of acute leukemia and 1.2% of allogeneic bone marrow transplantations at an institution where the rates of infection are increasing [1]. Risk factors for disease appear to be skin breakdown and paranychia. The degree of immunosuppression directly correlates with the risk of disseminated disease [1]. The mean duration of neutropenia among patients with disseminated infection was reported to be 16 days in 1 series [4]. In the same series, all nonneutropenic patients who presented with disseminated disease were immunosuppressed as a result of steroid therapy [4].

The presenting signs and symptoms of disseminated fusariosis include fever that is refractory to antibiotic therapy (in 90% of cases), skin lesions (in 70%–90% of cases) that are often disseminated (in 66% of cases), and pulmonary infiltrates or nodules (in 54% of cases) [1, 4]. All of these signs and symptoms were found in our patient. The skin lesions are typically ecthyma-like or target lesions [1, 4]. Diagnosis may be ascertained through blood culture (in 40% of cases) or biopsy of skin lesions. Skin lesions correlate with fungemia but usually precede bacteremia by up to 5 days [1].

Successful therapy of fusariosis has been reported with amphotericin B products, itraconzole, posaconazole, and voriconazole [1, 2, 5, 6]. One case report of successful therapy with an echinocandin has also been reported, although this agent has poor in vitro activity against Fusarium species [7–9]. The associated mortality rate is high (50%–80%) regardless of treatment, and death strongly correlates with persistent neutropenia or steroid use [4]. However, in the absence of these 2 factors, the survival rate approaches 70% [4]. Our patient continued to receive therapy with voriconazole, and his neutrophil count returned to normal on day 11 of hospitalization. There was rapid subsequent resolution of fever and cutaneous lesions and a diminution in the size of the pulmonary nodules, and the patient was discharged from the hospital.

Acknowledgments

We thank Maria Lavina for microbiology lab assistance.

Potential conflicts of interest. G.F. has received speaker's honoraria from Pfizer. C.P. and A.C.: no conflicts.