Sense of Smell, Taste Impaired after Common Cold

Q:  Six months ago, I had a bad cold. I went to the doctor and was told I had a "respiratory infection." It went on for 8 weeks! This is unusual for me: I'm a healthy, 49-year-old non-smoker and I almost never get sick. I haven't had more than two colds in 10 years.

Here is my concern: I still can't smell, and my ability to taste is very limited. This is frustrating, to say the least. Should I be worried?

A:  Problems with the sense of smell are common, but unfortunately, often overlooked, because smell is often not considered a vital function. However, as you can attest, smell is a valuable facet of human existence, and some people without a sense of smell can become depressed or even malnourished (as the joy of eating is lessened).

The sense of taste is separate from the sense of smell, but problems with taste alone are uncommon because there are so many nerve pathways from the tongue to the brain. Usually, problems with smell interfere with the flavor of food, where flavor is the whole food experience: smell, taste, texture, and temperature.

One of the most common causes of problems with the sense of smell is age: about 50% of those over age 60 years have decreased sense of smell. I don't think this is why you cannot smell, as you are still young (a 49-year-old is young, right?) and your problem is relatively sudden and severe.

The other most common causes are infection, inflammation, or obstruction of the nose and sinuses. The cold virus can damage smell receptors in the lining of the nose, and sometimes even the nerves that carry smell information to the brain. But recovery from a cold should occur within a couple months. If you had used a zinc nose spray to treat your cold (commonly done but not usually helpful), the zinc could have contributed to any damage.

There are uncommon causes of problems with the sense of smell, like a thyroid disorder, vitamin deficiencies, chemical exposure, and certain medications (e.g., blood pressure pills). Trauma, stroke and early Alzheimer and Parkinson's disease also can present with troubles with smell.

I don't think you need to worry about these uncommon causes yet, but I do think you should see your doctor to have a good examination of your nose and sinuses. You may have an allergy (instead of a cold) or a polyp or tumor blockading your nose passages.

Julie L. Mitchell, MD, MS, is an Assistant Professor of Medicine at the Medical College of Wisconsin. She practices at the Froedtert & The Medical College of Wisconsin General Internal Medicine Clinic - East. Her column appears in the Milwaukee Journal-Sentinel.