Medication Summary
Although not a true fungal disease, treatment with antifungals is effective and may be used in conjunction with surgical excision. When a patient shows resistance to one antifungal, susceptibility testing may be helpful to direct treatment. [22]
Antifungal Agent, Systemic
Class Summary
These agents exert a fungicidal effect by the following mechanisms: altering the permeability of the fungal cell membrane, altering RNA and DNA metabolism, and causing intracellular accumulation of peroxide.
Itraconazole (Sporanox)
Itraconazole has fungistatic activity. It is a synthetic triazole antifungal agent that slows fungal cell growth by inhibiting cytochrome P-450–dependent synthesis of ergosterol, a vital component of fungal cell membranes.
Voriconazole (Vfend)
Voriconazole is a triazole antifungal agent that inhibits fungal CYP450-mediated 14 alpha-lanosterol demethylation, which is essential in fungal ergosterol biosynthesis.
Fluconazole (Diflucan)
Fluconazole is a synthetic oral antifungal (broad-spectrum bistriazole) that selectively inhibits fungal cytochrome P-450 and sterol C-14 alpha-demethylation, which prevents conversion of lanosterol to ergosterol, thereby disrupting cellular membranes. It has little affinity for mammalian cytochromes, which is believed to explain its low toxicity. It is available as tabs for oral administration, as a powder for oral suspension, and as a sterile solution for IV use. Fluconazole has fewer adverse effects and better tissue distribution than older systemic imidazoles.
It can be used in severe or life-threatening infections in patients intolerant of amphotericin B, and it may be used for maintenance after a course of amphotericin B in coccidioidal meningitis. It penetrates well into cerebrospinal fluid. Metabolic clearance is prolonged in patients with renal dysfunction.
Amphotericin B (AmBisome)
Amphotericin B is for use in disseminated disease. It is produced by a strain of Streptomyces nodosus and can be fungistatic or fungicidal. Amphotericin B binds to sterols (eg, ergosterol) in the fungal cell membrane, causing intracellular components to leak, with subsequent fungal cell death.
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This subtle lesion of cutaneous protothecosis on the shoulder shows an ill-defined, slightly erythematous, thin plaque.
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Periodic acid-Schiff–stained sections of protothecosis reveal rounded endospores that form characteristic moruloid structures in the dermis.
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Electron photomicrograph of Prototheca wickerhamii shows a central rounded endospore surrounded by a corona of molded endospores.
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Biopsy reveals morula structures surrounded by lymphocytes and histiocytes (hematoxylin and eosin–stained sections; 200x).
