Olfactory loss and allergic rhinitis.

Olfactory loss is of importance for allergists to investigate in their patients, because if it is due to either allergic rhinitis or nonallergic rhinitis, it is potentially reversible. One should be sure to consider nasal polyposis and inflammation from chronic sinusitis, especially of the ethmoidal sinuses. Simple screening in the office can be achieved with an odor identification test of widely available substances as described above. Should there be no response to treatment or if the patient has a history of chronic sinusitis, recalcitrant nasal polyposis, or previous otolaryngologic procedures, further evaluation including rhinoscopy may be required. Recent olfactory loss in the absence of nasal symptoms and in the absence of abnormalities in the nasal cavity should suggest further investigation to look for a more central process. Morphologic investigation with electron microscopy of the olfactory epithelium and the superior nasal cavity is just beginning. The impact of inflammation in this area awaits investigation.