Sinusitis, or more accurately rhinosinusitis, is a common disorder affecting approximately 20% of the population at some time of their lives. Fungal rhinosinusitis, once considered a rare disorder, is being recognized and reported with increasing frequency over last two decades worldwide (1-3). Aspergillus is the most common reported cause of fungal rhinosinusitis (2,3). Fungal rhinosinusitis occurs in two distinct clinical settings: fulminant invasive disease is seen in patients with immuno-suppression and chronic fungal rhinosinusitis in apparently healthy hosts (4). The fulminant variety, similar to rhino-cerebral zygomycosis, is well known to clinicians due to its dramatic presentation and poor prognosis. But the existing knowledge regarding chronic fungal rhinosinusitis is quite controversial and often confusing. Even whether fungi can exist in sinus mucous without causing disease is unclear. Chronic fungal rhinosinusitis is not uniform single entity, rather represents multiple disorders/presentations: allergic, fungal ball (sinus mycetoma), chronic invasive, granulomatous invasive. Each has different outcome of fungus–host interaction (5). Controversy remains whether these are separate category of chronic fungal rhinosinusitis or a spectrum of single diseases (6). Though chronic fungal rhinosinusitis is seen worldwide, the incidence in tropical countries like India, Sudan, Pakistan, Saudi Arabia etc. is very high with some peculiar interesting observations (7-12):

• Aspergillus flavus is the commonest etiological agent in all forms of chronic fungal rhino-sinusitis in these countries in contrast to A. fumigatus in other countries.
• Even in allergic fungal rhinosinusitis, A. flavus is the commonest etiological agent contrasting to phaeoid mycelial fungi in other countries.
• Granulomatous invasive fungal rhinosinusitis is possibly curious syndrome prevalent in these countries.

References

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10. Panda NK, Sharma SC, Chakrabarti A, Mann SBS. Paranasal sinus mycoses in north India. Mycoses 1998; 41: 281-6.
    
11. Thakar A, Sarkar C, Dhiwakar M, Bahadur S, Dahiya S. Allergic fungal sinusitis: expanding the clinicopathological spectrum. Otolaryngol Head Neck Surg 2004; 130: 209-16.
    
12. Chakrabarti A, Das A, Panda NK. Overview of fungal rhinosinusitis. Indian J Otolaryngol Head Neck Surg 2004; 56: 251-8.