Phaeohyphomycosis refers to infections caused by dark, melanin-pigmented dematiaceous fungi. It is distinguished from chromoblastomycosis and mycetoma by the absence of specific histopathologic findings. Treatment is with itraconazole or sometimes with other triazoles or terbinafine.
(See also Overview of Fungal Infections.)
Phaeohyphomycosis can be caused by many species of dark, melanin-pigmented dematiaceous fungi including Bipolaris, Cladophialophora, Cladosporium, Exophiala, Fonsecaea, Phialophora, Ochronosis, Rhinocladiella, and Wangiella.
Although some species of these fungi may cause phaeohyphomycosis in immunocompetent patients, pigmented fungi have been increasingly recognized as opportunists; almost all cases of disseminated infection occur in immunosuppressed patients. Dematiaceous fungi only rarely cause fatal infections in patients who have intact host defense mechanisms; however, certain species (mainly Cladophialophora bantiana) may cause brain abscess in immunocompetent patients (1).
Clinical syndromes include invasive sinusitis, sometimes with bone necrosis, as well as subcutaneous nodules or abscesses, keratitis, lung masses, osteomyelitis, mycotic arthritis, endocarditis, brain abscess, and disseminated infection.
General reference
1. Revankar SG, Sutton DA, Rinaldi MG. Primary central nervous system phaeohyphomycosis: a review of 101 cases. Clin Infect Dis. 2004;38(2):206-216. doi:10.1086/380635
Diagnosis of Phaeohyphomycosis
Examination using Masson-Fontana staining
Culture to identify causative species
Dematiaceous fungi can frequently be discerned in tissue specimens stained with conventional hematoxylin and eosin; they appear as septate, brownish hyphae or yeast-like cells, reflecting their high melanin content. Masson-Fontana staining for melanin confirms their presence (1).
Phaeohyphomycosis is distinguished from chromoblastomycosis and mycetoma by the absence of specific histopathologic findings such as sclerotic bodies or grains in tissue.
Culture is needed to identify the causative species.
Diagnosis reference
1. Chowdhary A, Meis JF, Guarro J, et al. ESCMID and ECMM joint clinical guidelines for the diagnosis and management of systemic phaeohyphomycosis: diseases caused by black fungi. Clin Microbiol Infect. 2014;20 Suppl 3:47-75. doi:10.1111/1469-0691.12515
Treatment of Phaeohyphomycosis
For subcutaneous nodules, surgery and/or itraconazole
For brain abscess or disseminated infections, a combination of antifungals
(See also Antifungal Medications.)
There is no standard therapy; treatment of phaeohyphomycosis depends on the clinical presentation and immune status of the patient.
For subcutaneous nodules, surgery alone may be curative. Itraconazole has excellent activity and has been most commonly used, although voriconazole has been increasingly used with excellent results (surgery alone may be curative. Itraconazole has excellent activity and has been most commonly used, although voriconazole has been increasingly used with excellent results (1). Duration of therapy varies but may range from 6 weeks to > 12 months. Posaconazole is a well-tolerated alternative agent, but there is less clinical data in this setting compared with other antifungal agents (). Duration of therapy varies but may range from 6 weeks to > 12 months. Posaconazole is a well-tolerated alternative agent, but there is less clinical data in this setting compared with other antifungal agents (2).
For brain abscess, treatment should include surgical resection if possible.
For brain abscess or disseminated infections, combination therapy (eg, with 2 or 3 medications, at least one of which is an azole) is often used; however, clinical outcomes are generally poor regardless of treatment (2).
Amphotericin B has been useful in some cases. Amphotericin B has been useful in some cases.
Treatment references
1. Noguchi H, Matsumoto T, Kimura U, et al. Empiric antifungal therapy in patients with cutaneous and subcutaneous phaeohyphomycosis. J Dermatol. 2022;49(5):564-571. doi:10.1111/1346-8138.16312
2. Chowdhary A, Meis JF, Guarro J, et al. ESCMID and ECMM joint clinical guidelines for the diagnosis and management of systemic phaeohyphomycosis: diseases caused by black fungi. Clin Microbiol Infect. 2014;20 Suppl 3:47-75. doi:10.1111/1469-0691.12515
Drugs Mentioned In This Article
