TOPICS: Nasal cavity, paranasal sinuses, viruses, rhinovirus, influenza, parainfluenza, bacteria, fungal, immunosuppression, maxillary, frontal, sphenoid, ethmoid, middle meatus, nasal congestion, purulent nasal drainage, hyposmia, opacity, transillumination of sinuses, local spread, periorbital cellulitis, orbital cellulitis, meningitis, cavernous sinus syndrome, intracranial abscess, osteomyelitis