Loss of smell can occur after head trauma or as a complication of nasal or sinus infections, including viral illnesses. Chemical toxicity can be another cause. I once evaluated the owner-operator of a fish-processing plant who had been overcome at work by a concentrated ammonia leak from an industrial refrigeration system. His sensory loss improved over time, but he complained of no longer being able to recognize many familiar smells, such as his wife's perfume or freshly mown grass.

Zinc is an interesting substance, one of a group of metallic elements that are necessary nutritional factors for normal bodily functioning. This does not mean, however, that zinc is benign. Although too little may be detrimental, too much can be hazardous, too and, depending on the form of the metal and the route by which it enters the body, differing untoward effects can occur.

What about zinc gluconate, especially if applied to the nose - might a toxic loss of smell have been anticipated? Sadly, the answer is yes. In the late 1930s, zinc sulfate was touted a preventive treatment for a viral infection far more sinister that than common cold - poliomyelitis. Known then as the Peet-Schultz nasal spray, zinc sulfate was purported to protect again this dreaded disease. In the Fall of 1937, Time Magazine went so far as to speculate,"...This promises to be a light year for infantile paralysis. How much this may be due to the preventive effect of the Peet-Schultz nasal spray is any epidemiologist's guess." By 1938 though, a brief but convincing scientific report in the Journal of Pediatrics documented that loss of both taste and smell was unacceptably common among children who had received zinc sulfate nasal treatments. Such prophylaxis (which in any event was of unclear efficacy) soon fell into disfavor.

Based on this experience, nasally-applied zinc gluconate should have raised legitimate concerns before it was ever marketed in the first place. Then, as might have been feared, by 2004 a medical report of impaired smell in 10 patients due to nasal zinc gluconate appeared in a peer-reviewed journal; less than two years later, a more detailed series of 17 additional patients seen at a different medical center was documented in another medical journal.

The FDA has documented 130 cases of loss of smell over almost a decade of accumulating injury; it believes that Zicam has had more than 800 such reports of its own. The FDA has demanded that details of these be turned over the agency. For a licensed drug, this would have been automatic. But as "homeopathic" agents, the Zicam product line has avoided this as well as a series of other requirements related to medication safety, effectiveness, and labeling. In tackling the long smoldering case of nasal zinc gluconate, the FDA may be sending an important signal that its oversight may be intensified for a wide range of over-the-counter treatments, including supposedly "natural" cures of various stripes and colors. It's about time.

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Tags: acute loss, ammonia leak, chemical toxicity, cold remedies, cold remedy, environment, fish processing, food and drug administration, food and drug administration fda, head trauma, health, industrial refrigeration, loss of smell, matrixx initiatives inc, metallic elements, mown grass, nutritional factors, refrigeration system, sinus infections, untoward effects, viral illnesses, zinc gluconate