| Abstract|| |
Allergic fungal rhinosinusitis (AFRS) forms a significant group of patients presenting with the commonest health problem encountered in rhinology. Patients commonly present with typical symptoms of sinusitis, and the diagnosis is often made after imaging and/or intraoperatively. Infections caused by Chrysosporium species are very rare and are very rarely been reported to cause sinusitis in humans. Usually, human chrysosporial infections are mild and unmarked by symptoms. We report a rare case of allergic fungal sinusitis (AFS) caused by Chrysosporium species in a 41-year-old male with the history of diabetes mellitus.
Keywords: Allergic, Chrysosporium, sinusitis
|How to cite this article:|
Shrivastava J, Shah K, Shah N. Chrysosporium: A rare cause of allergic fungal rhinosinusitis. Indian J Pathol Microbiol 2023;66:611-3
| Introduction|| |
Members of the genus Chrysosporium are common soil saprobes, many of which are keratinophilic fungi involved in the breakdown of shed keratinous substrates. It belongs to the Phylum Ascomycota, Order Onygenales, and Family Onygenaceae. The genus Chrysosporium contains several species. The most common ones are Chrysosporium keratinophilum, Chrysosporium tropicum, Chrysosporium medarium, Chrysosporium inops, Chrysosporium queenslandicum, and Chrysosporium zonatum. Another species of special interest classified as Emmonsia parva on the ecological basis is occasionally named Chrysosporiumparvum as well. Chrysosporium species may cause skin infections and onychomycosis in humans. In addition to these superficial infections, Chrysosporium species have occasionally been isolated from systemic infections in bone marrow transplant recipients and patients with the chronic granulomatous disease (CGD). The high mortality rate of systemic Chrysosporium infections is noteworthy. These fungi are encountered occasionally in the diagnostic laboratory predominantly as contaminants of cutaneous or respiratory specimens. They mimic true dermatophytes or dimorphic pathogens. In humans, there are only rare reports of deep infection caused by the species of Chrysosporium. We report a case of allergic rhinusinusitis of Chrysosporium species
| Case History|| |
A 41-year-old male patient presented to the ENT department with the complaint of watery nasal discharge, nasal blockage, and headache for 4 months. He was known case of type ll diabetes mellitus with the fasting blood sugar 227 mg/dL and postprandial blood sugar 330 mg/dL and on antidiabetic medications. His serum IgE (310 UI/mL) was also raised.
The diagnostic nasal endoscopy did not reveal any gross abnormality except for a deviated nasal septum to the right, mucosal discharge on the right nasal cavity, and polypoidal mucosa over the right middle turbinate. CT scan of the nose and paranasal sinuses showed gross mucosal thickening involving right all paranasal sinuses with near-total opacification with the widening of osteomeatal unit with soft tissue extending into the right nasal cavity completely obliterating and inseparable from the right nasal turbinate which gave the impression of fungal sinusitis involving the right paranasal sinuses and nasal cavity. Right functional endoscopic sinus and septoplasty surgery was done to clear out the disease from sinuses. Intraoperatively, fungal debris and mucin with mucosal hypertrophy were sent for microbiological examination.
Microbiological examination confirmed the presence of the fungus on potassium hydroxide preparation with thin, tortuous, hyaline branching occasionally septate hyphae. On Sabouraud's dextrose agar after 1 week of incubation white cottony growth with reverse yellowish tan was observed [Figure 1].
|Figure 1: On Saborauds dextrose agar white cottony growth with reverse yellowish tan|
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On lactophenol cotton blue preparation, septate hyphae with a stalk-like, conidiophores bearing conidia directly on the hyphae were seen [Figure 2].
|Figure 2: Intercalary arthroconidia andseptate hyphae with stalklike, conidiophores bearingconidia directly on the hyphae|
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Conidia were one-celled, clavate, with a rounded apex and broad flattened base. Intercalary conidia were also seen.
Chrysosporium differs from Blastomyces by being nondimorphic, from Microsporum and Trichophyton by lacking macroconidia, from Geomyces by lacking branched, fertile hyphae on erect conidiophores, and from Sepedonium by having hyaline conidia.
Based on morphological features, it was identified as Chrysoporium spp.
| Discussion|| |
AFRS is a noninvasive form of fungal rhinosinusitis. It is common among adolescents and young adults and is more common in geographical areas of high humidity. Two-thirds of patients are atopic and half suffer from asthma. Two-thirds of allergic fungal sinusitis patients suffer from allergic rhinitis, and approximately 90 percent have increased blood levels of immunoglobulin E.
It is believed that fungal allergens elicit immunoglobulin E- (IgE-)–mediated allergic and possibly type III (immune complex)–mediated mucosal inflammation in the absence of invasion, in an atopic host. To diagnose AFRS, Bent III and Kuhn in 1994 proposed five diagnostic criteria: type I hypersensitivity, nasal polyposis, characteristic findings on CT scan, presence of fungi on direct microscopy or culture, and the accumulation of eosinophilic (allergic) mucin (a thick, tenacious eosinophilic secretion, containing fungal elements without tissue invasion). But in 1994, Cody II et al. reported the Mayo Clinic experience and suggested that diagnostic criteria comprise only the presence of allergic mucin and fungal hyphae or a positive fungal culture. In our patient, most of the criteria were fulfilled including raised IgE levels.
Chrysosporium is rarely seen in fungal debris or allergic mucin isolated from sinuses. Chrysosporium is a poorly known, thermotolerant, and keratinophilic species. Such fungi are encountered in the diagnostic laboratory predominantly as contaminants. Infection is caused due to exposure to airborne conidia.
Susceptibility data from previous studies suggest that the organism is susceptible to amphotericin-B and moderately resistant to itraconazole. However, standardized values are not available, recent studies have also noted the effectiveness of systemic voriconazole in Chrysosporium infection although our patient was given tab fluconazole and nasal douching to clean the sinus cavity and prevent biofilm formation which promotes the growth of healthy nasal mucosa. The patient had relief on follow-up.
| Conclusion|| |
Chrysosporium is one of the rarest causes of AFRS with very few cases reported till date. The Bent and Kuhn criteria are generally the most widely accepted diagnostic criteria in use today. Theories on pathogenesis include hypersensitivity and T-cell–mediated reactions as well as a humoral immune response. Regardless of the fungus isolated, debridement proves to be the best modality of treatment although systemic antifungals do play an adjuvant role in AFRS.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]