Duane R. Hospenthal, MD, PhD

Sporotrichosis is a fungal infection that typically results in cutaneous or lymphocutaneous disease, although other, more severe, life-threatening manifestations do occur. This article reviews updated treatment guidelines, which state that itraconazole has become the preferred therapy for most forms of infection. Amphotericin B remains the mainstay of treatment for severe cases, but lipid formulations are now preferred because of their more favorable toxicity profile. Also, fluconazole has been shown to be less effective than itraconazole and is no longer recommended except as an alternative for cutaneous and lymphocutaneous disease. [Drug Benefit Trends. 2010;22:49-52]

Histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum, which is endemic to the Ohio and Mississippi river valleys. It is associated with a variety of manifestations, and its severity ranges from asymptomatic infection to severe disseminated illness.

Posaconazole, indicated for prophylaxis of invasive Aspergillus and Candida infections in immunosuppressed patients aged 13 years or older and for treatment of oropharyngeal candidiasis (Table 1), is like other triazole antifungals in that it blocks ergosterol biosynthesis. 1 Its chemical structure is most similar to that of itraconazole (Figure), which may confer efficacy even against strains resistant to fluconazole and voriconazole.2

Over the past 2 decades, there has been an alarming increase in opportunistic fungal infections with an associated rise in morbidity and mortality. This trend has been attributed to the growing number of patients who are immunocompromised because of bone marrow or solid organ transplant, immunosuppressive drugs, AIDS, and hematological malignancies. Advances in trauma and critical care medicine that lead to longer survival of more patients with immunocompromising conditions also play a role.

Filamentous fungi (molds) can be divided into 2 broad morphologically distinct groups: those that produce aseptate hyphae and those that produce aseptate (or rarely septated) hyphae. Identification of aseptate hyphae in tissue is virtually pathognomonic of zygomycosis (mucormycosis)-disease caused by fungi of the class Zygomycetes (order Mucorales). The discovery of septate hyphae in tissue is less diagnostic; septate hyphae may be caused by fungi that typically grow as yeasts (eg, Candida and Trichosporon) or a vast number of species of molds. The septate molds are often divided into those with darkly pigmented hyphae (phaeohyphomycetes) and those with pale or colorless (hyaline) hyphae (hyalohyphomycetes).