Pediatric Phaeohyphomycosis: A 44-Year Systematic Review of Reported Cases

BACKGROUND

Phaeohyphomycosis is an infection caused by pigmented fungi, which can be life-threatening in immunocompromised hosts and in disseminated disease. In adults with disseminated disease, mortality is as high as 79%. Data in children are derived from case reports and series. We conducted this study to review the characteristics of phaeohyphomycoses in children.

METHODS

We conducted this study following the PRISMA 2020 guideline for reporting systematic reviews. We performed a review of the reported cases of pediatric phaeohyphomycoses in core bibliographic databases published in the English and Spanish language, between June 1977 and October 2021. We included all eligible cases in patients <18 years to determine the clinical characteristics, diagnosis, treatment, and outcomes.

RESULTS

A total of 130 cases were reviewed. The mean age was 8 years. The most common underlying conditions and risk factors included hematologic malignancies (32.5%), neutropenia (26.9%), steroid therapy (24.6%), trauma or surgery (23.1%), and children that received a transplant (14.6%). The most common presentation was localized infection (61.5%); skin and soft tissue infections were the most prevalent (25.4%). Exserohilum spp (20.8%) and Exophiala spp (17.7%) were the most common organisms isolated. Antifungal therapy remains as the most frequent treatment (87%). Overall mortality rate was 22.3% (localized 13.7% vs disseminated 37.3%).

CONCLUSION

The findings of this review suggest that phaeohyphomycoses in children have a better outcome compared to adults. We report a lower mortality rate in children when compared with adults in disseminated infection (37.3% vs 79%) and CNS infection (50% vs 60-70%). However, there is a wide variation in mortality rates according to the infection site, treatment, and underlying conditions. Prospective studies are needed.

Phaeohyphomycosis in China

Background

Due to more attentions paid to melanized fungi over the past few decades and under the background of the global coronavirus disease 2019 pandemic (COVID-19) the fact that the virus itself and the immunosuppressive agents such as glucocorticoids can further increase the risk of infections of deep mycoses, the number of patients with phaeohyphomycosis (PHM) has a substantial increase. Their spectrum is broad and the early diagnosis and treatments are extremely sticky. This study aims to more comprehensively understand the clinical features of phaeohyphomycosis in China over 35 years and to establish a more applicable systematical classification and severity grades of lesions to guide treatments and prognosis.

Methods

We reviewed 174 cases of proven phaeohyphomycosis reported in Chinese and English language literature from 1987 to 2021 and we also made the accurate classification definitions and detailed information about the epidemiology, species of clinical dematiaceous fungi, minimum inhibitory concentration values, clinical features, treatments, and prognosis.

Results

The mortality of cerebral, disseminated and pulmonary phaeohyphomycosis are 55%, 36%, and 25%. Nearly 19% of patients had poor quality of life caused by the complications such as disability, disfigurements, and blindness. The overall misdiagnosis rate of phaeohyphomycosis was 74%. Moderate to severe rashes are accounting for 82% of subcutaneous phaeohyphomycosis. The areas of the head and face are mostly affected accounting for 16% of severe rashes. Nearly 30% of invasive infections of phaeohyphomycosis are triggered by recurrent lesions. Voriconazole, itraconazole, amphotericin B deoxycholate (AmB-DOC), and terbinafine were most commonly used but diagnosis and treatments of phaeohyphomycosis remain challenging in reality.

Conclusions

Our classifications are likely to be more practical and easier to popularize, and there are still also plenty of characteristics in these non-specific lesions. There’re no significant variations in cure rates, or death rates between three grades of lesions. But patients with severe rashes have longer courses and lower effective rates.

Retrospective study of phaeohyphomycosis in aquarium-housed fish, with first descriptions of Exophiala lecanii-corni and Neodevriesia cladophorae in fish

A broadening fish host range is affected by novel and known pigmented fungal pathogens. A review of 2,250 piscine submissions received by the Aquatic Pathology Service, University of Georgia, revealed 47 phaeohyphomycosis cases (2.1%), representing 34 bony and cartilaginous fish species. The majority involved bony fish (45/47, 95.7%) and were predominantly marine (41/47, 87.2%), with only a few freshwater species (4/47, 8.5%). Cartilaginous fish cases included two zebra sharks (Stegostoma fasciatum) (2/47, 4.3%). Northern seahorses (Hippocampus erectus) had the highest incidence overall (7/47, 14.9%). Culture and sequencing of the internal-transcribed spacer region of the rDNA (ITS), large ribosomal subunit gene D1/D2 domains (LSU) and the DNA polymerase II gene (RPB2) were performed for fungal identification when fresh tissue was obtainable. Exophiala, Ochroconis and Neodevriesia spp. were identified, with Exophiala as the most common fungal genus (8/11, 72.7%). Exophiala lecanii-corni and Neodevriesia cladophorae were described for the first time from fish. Microscopically, lesions were characterized by necrosis, granulomatous inflammation and angioinvasion most frequently affecting the skin/fin, skeletal muscle and kidneys. In this study of diverse aquarium-housed fish species, phaeohyphomycosis cases occurred sporadically and in rare outbreaks with variable pathologic presentations, tissue distributions and severities.

Phaeohyphomycosis resulting in obstructive tracheitis in three green sea turtles Chelonia mydas stranded along the Florida coast

Three wild immature green sea turtles Chelonia mydas were found alive but lethargic on the shores of the Indian River Lagoon and Gulf of Mexico in Florida, USA, and subsequently died. Necropsy findings in all 3 turtles included partial occlusion of the trachea by a mass comprised of granulomatous inflammation. Pigmented fungal hyphae were observed within the lesion by histology and were characterized by culture and sequencing of the internal transcribed spacer 2 domain of the rRNA gene and D1/D2 region of the fungal 28s gene. The dematiaceous fungus species Veronaea botryosa was isolated from the tracheal mass in 2 cases, and genetic sequence of V. botryosa was detected by polymerase chain reaction in all 3 cases. Genetic sequencing and fungal cultures also detected other dematiaceous fungi, including a Cladosporium sp., an Ochroconis sp., and a Cochliobolus sp. These cases are the first report of phaeohyphomycosis caused by V. botryosa in wild marine animals.

Bipolaris hawaiiensis as an emerging cause of cutaneous phaeohyphomycosis in an Antillean manatee Trichechus manatus manatus

Phaeohyphomycoses are emerging and opportunistic diseases caused by dematiaceous fungi that infect many animal species. This paper describes a case of cutaneous phaeohyphomycosis in an Antillean manatee Trichechus manatus manatus caused by Bipolaris hawaiiensis. Blackish skin lesions were observed in an Antillean manatee calf held captive in Brazil. Direct examination of skin scraping from the affected areas revealed the presence of dematious hyphae. Culture of skin fragments led to the isolation and subsequent identification of B. hawaiiensis as the etiologic agent. Treatment with itraconazole for 14 d was effective. Infections by Bipolaris spp. are rare in animals, and this is the first report of B. hawaiiensis in veterinary medicine.