Paranasal sinus mycoses

The incidence of paranasal sinus mycoses (fungal sinusitis) varies widely with higher frequency in Sudan, southwestern states of USA and north India, which have hot and dry climate. The disease has been described as having four types: allergic, non-invasive, invasive and fulminate. A possible fifth type: non-invasive destructive may also exist. In a prospective study of 176 cases of fungal sinusitis from our centre, on the basis of clinical, radiological, histopathologic and mycologic findings the patients could be categorized into: allergic (12), non-invasive without bone destruction (81), non-invasive destructive (16), chronic invasive (55) and fulminant (12) types. Except the fulminate variety, the disease is commonly found in young immuno-competent population of rural areas. Aspergillus spp. are the commonest etiological agents though the importance of dematiaceous fungi in allergic fungal sinusitis has been stressed. Zygomycetes are common agents in fulminate type. In our series A. flavus (80%) was the commonest isolate, followed by A.fumigatus (9.7%), Rhizopus arrhizus (6.3%) and Alternaria spp. (1.1%). Curvularia lunata, Apophysomyces elegans and Candida albicans were isolated from one patient each. Different host and environmental factors may help in lodging the causal fungi in mucosal plugs of these patients. Fungal allergy is associated with all varieties of the disease. But it is not clear what determines the invasion of mucosa. Rabbit can be used as an animal model. Histopathology and radio-imaging techniques help to distinguish different types and delineate extension of disease process. Culture helps to identify the responsible etiological agent. The presence or absence of precipitating antibody correlates well with disease progression or recovery. For effective management, non-invasive disease requires surgical debridement and sinus ventilation only. But for invasive type the need of adjuvant medical therapy is recommended to prevent recurrence and further extension. Itraconazole was found to be most useful in our study to prevent recurrence. Patients with fulminate type require radical surgery and immediate chemotherapy.