Fungal forms of chronic rhinosinusitis are less common than bacterial ones, but they can be serious if not adequately treated. For more serious manifestations please see invasive FRS
AFRS (allergic fungal rhinosinusitis) presents with nasal obstruction, loss of smell, nasal discharge (productive sneezing and/or postnasal mucus) and a pressure sensation over the face sinus area are the commonest symptoms. Most patients have nasal polyps when they first present and if they relapse. A chronic presentation is usual, but occasionally an acute presentation with double vision or visual loss, distortion of facial features through pressure effects with complete nasal obstruction. Production of nasal crust is usual. Asthma is also common, but not always severe. Occasionally patients also have ABPA (the so-called Sino-bronchial Allergic Mycosis or SAM syndrome). Salicylate sensitivity should be excluded, as an alternative management approach is required.
– Read a review: Singh (2019) or Medikevi & Javer (2020)
The predominant fungus responsible varies geographically but includes Aspergillus fumigatus, A. flavus, Bipolaris spicifera, Curvularia lunata, Alternaria alternata and other dematiceous (brown) fungi. Alternaria alternata and other dematiceous fungi predominate in USA, A. flavus in middle east, India and Pakistan.
Worldwide and probably common in adults; uncommon in childhood. AFRS and EFRS are estimated to affect ~12 million people at any time, based on the fact that chronic rhinosinusitis affects ~15% of the world’s population at some point in their life (i.e.around 900 million people) and ~1.3% is predominantly fungal in origin.
CT or MRI of the sinuses show complete opacification of more than one paranasal sinus, usually with expansion of involved sinuses. With the mucus found in the sinuses, there is usually heterogeneity of signal and there is often thinning or erosion of the bone bordering involved sinuses. Disease may unilateral or asymmetric. Sometimes there is displacement of adjacent anatomic compartments.
The key finding is the presence of eosinophilic mucin (pathology showing degranulating eosinophils). Fungal hyphae may be seen in the mucus and are not found across the mucosa (if they are then the disease is invasive). Often, the diagnosis becomes difficult when the mucus is discarded and not submitted to the laboratory. So both submission of mucus and cytopathological examination of that mucus with fungal stains is required to establish the diagnosis with confidence (lab methods)
With AFRS, over 90% of patients have a positive fungal skin test or elevated fungal-specific IgE; whereas in EFRS, skin tests or elevated fungal-specific IgE for fungi are usually negative.
Surgical eradication of all allergic mucin and simultaneously providing permanent drainage and aeration of the affected sinuses is the cornerstone of management. This is often achieved with endoscopic surgery, but each patient’s needs an individual assessment. Handling the ethmoidal sinuses is particularly important in achieving a good outcome. Post-operative nasal corticosteroids probably reduce recurrence. Saline douching may also assist in mucous clearance. Oral corticosteroids possibly minimise recurrence better than a local steroid, but have the problems of long term side-effects. Intensive oral antibiotic therapy of intercurrent bacterial infections, reduces subsequent symptomatology. Immunotherapy may have some role in minimising recurrence.
The role of antifungal therapy is limited or zero, with current treatments. In frequenting relapsing disease, some patients appear to stabilise with long term oral itraconazole
Aggressive medical management can result in long term remission, but many patients have relapses months or years after surgical clearance.
Clinical images & videos
Visit our playlist of AFRS cases at Radiopaedia to view CT images and case histories.