DESTIN, FLA. Phaeohyphomycosis usually results from infection by Bipolaris fungi, and it requires wide debridement and immediate treatment with massive doses of itraconazole to reduce the fungal burden, Dr. Dirk Elston said at a meeting sponsored by the Alabama Dermatology Society.
Because the typical empirical treatments for more common fungal infectionssuch as amphotericinwill not work in this potentially fatal condition, consider this diagnosis, particularly in immunocompromised patients, who tend to develop invasive disease, he advised.
A quick biopsy and a good dermatopathologist are key. "You've got a window of opportunity to treat [these patients]. You have one chance to treat them right, and even with the right treatment they may succumb. But without that, they don't even have a chance," said Dr. Elston, who is director of the department of dermatology at Geisinger Medical Center in Danville, Pa.
Clues to the diagnosis are the presence of a thick refractile wall (as seen with mucormycosis) on histology, and bubbly cytoplasm (as seen with aspergillus or fusarium).
"You've got it nailed based on that [combination]. It's a black mold, a phaeo organism," he said.
He described a case involving a ventilator-dependent infant who developed what appeared to be multiple bedsores. Because of the ventilator, nurses had been unable to rotate the baby, who was born at 22 weeks' gestation in a septic environment following a car accident that resulted in a traumatic placental abruption in the mother.
When the infant was finally able to be rotated, the nurses discovered the lesions. A closer look revealed that the lesions were not bedsores, but fungal sepsis.
The lesions consisted of a black, leathery, depressed central eschar and an "almost bullous edematous scalloped border," Dr. Elston explained, noting that they appeared similar to fungal embolic lesions that occur commonly in leukemia patients.
A biopsy was performed and phaeohyphomycosis was diagnosed, but the infant died despite aggressive therapy. An autopsy revealed that the fungus had invaded every organ in the child's body, he said.
In another case, a diabetic patient with contact dermatitis from his shoes developed invasive phaeohyphomycosis that resulted in bilateral above-the-knee amputations.
"They basically chopped his legs off a bit at a time, starting with forefoot, then hindfoot, then [below-the knee amputation], then above-the-knee, as this plowed through tissue" he said, noting that the patient was never put on itraconazole but was treated with amphotericin.
"The wrong drug [was used] … so nailing the organism is really important for this," he said, reiterating the need for early diagnosis to determine the appropriate course of treatment.
Common manifestations of phaeohyphomycosis include tinea nigra, particularly in hot, humid climates, and phaeohyphomycotic cysts. These tend to develop in immunocompetent patients with these types of infections, whereas invasive disease occurs almost exclusively in immunocompromised patients, Dr. Elston said.
Morphology, rather than a Fontana-Masson stain for the characteristic melanin in the cell wall, should be relied upon for diagnosis in these infections, because Fontana-Masson will stain melanin in a variety of other conditions as well, he noted.