Neurotoxic Exposure and Olfactory Impairment

Normal functioning of the olfactory system is a prerequisite for the detection of several chemical environmental hazards (e.g., spoiled foods, leaking natural gas, smoke and various airborne pollutants), and for the full appreciation of foods, beverages, flowers, perfumes, spices, the seashore, the mountains, and the seasons of the year. Distortions or loss of smell function can adversely influence food preferences, food intake, and appetite, and in some cases can lead to significant psychological depression. It is thus no wonder that dysfunction of olfaction is of considerable concern to persons who experience it, particularly those dependent on this sense for their livelihood or safety (e.g., cooks, homemakers, plumbers, fire fighters, perfumers, fragrance sales persons, wine merchants, coffee or tea tasters, food and beverage distributors, and employees of numerous chemical, gas, and public works industries). Although smell dysfunction secondary to toxic exposure is generally less common than smell dysfunction caused by a number of other causes (e.g., upper respiratory infections, head trauma, chronic rhinitis or rhinosinusitis), it nonetheless exists. In addition to directly damaging the olfactory mucosa, some toxins may, in fact, induce upper respiratory inflammatory responses or infections that produce such damage, as well as enter the central nervous system (CNS) and cause damage to CNS structures. Olfactory loss can occur as a result of exposure to toxins in general air pollution and in workplace situations, where litigation becomes a consideration. Most cases of toxin-related olfactory loss do not get referred to specialized centers such as ours for evaluation. In fact, smell function is rarely