Diagnosis

Fungal rhinosinusitis should be considered in all patients with chronic rhinosinusitis, especially in association with certain clinical features like intractable symptoms despite adequate treatment for bacterial sinusitis, allergic rhinitis, asthma, nasal polyposis (non-invasive types) or fever, headache, epistaxis, diabetes, nasal mucosal ulcer, orbital apex syndrome, proptosis (invasive types) (1). The diagnosis of fungal rhinosinusitis depends on direct microscopical examination, culture and histopathology of tissue or the cheesy material obtained from sinuses. Direct microscopy helps in early diagnosis of fungal etiology and culture helps in identification of the etiological agents. Histopathology is important to distinguish the invasive type from the non-invasive type.

For the diagnosis of AFRS, the following criteria should be met: Type I hypersensitivity, detection of fungal elements, allergic mucin without fungal invasion, Charcot–Leyden crystals, bony erosion, and heterogeneous opacity with sinus expansion on CT (2, 3, 4). However, the diagnostic dilemma of this condition is already described.

Radiology plays important role in diagnosis of fungal rhinosinusitis. Conventional plain-film radiography may be used as a screening method for various pathological conditions of sinonasal cavities. However, CT scanning remains the study of choice for the imaging evaluation of acute and chronic inflammatory disease of sinonasal cavities. MRI is superior to CT in differentiating inflammatory conditions from neoplastic processes and intracranial extensions (5).

Several serological tests are performed to evaluate host defenses with fungal rhinosinusitis. Precipitin antibody detection and skin test may help in preliminary screening of patients and during recurrence (6).

References

1. deShazo RD, Chapin K, Swain RE. Fungal sinusitis. New Eng J Med 1997; 337: 254-9.
2. Saravanan K, Panda NK, Chakrabarti A, Das A, Bapuraj RJ. Allergic fungal rhinosinusitis: an attempt to resolve the diagnostic dilemma. Arch Otolaryngol Head Neck Surg 2006; 132: 173-8.
3. Schubert MS. Allergic fungal sinusitis: pathogenesis and management strategies. Drugs 2004; 64: 363-74.
4. Bent J, Kuhn FA. Diagnosis of allergic fungal sinusitis. Otolaryngol Head Neck Surg 1994; 111: 580-8.
5. Mafee MF, Tran BH, Chapa AR. Imaging of rhinosinusitis and its complications. Clin Rev Allergy Immunol 2006; 30: 165-85.
6. Chakrabarti A, Sharma SC, Chander J. Epidemiology and pathogenesis of paranasal sinus mycoses. Otolaryngol Head Neck Surg 1992; 107: 745-50.