Q: About 10 months ago I started noticing that I couldn’t smell. I had a major incident where natural gas was blowing out of a clipped line and I never even smelled it at all. I went to an ENT but he put me on antibiotics twice over a two month period that didn’t work. He said that between one and two percent of the population report a loss of smell and taste a year. Can you tell me as much about this as you know? Is it true it could be early signs of Parkinson’s or Alzheimer’s? Have you suffered from lead poisoning

A: Loss of smell results from conditions that affect the mucous membranes that line nasal passages. There are countless possible causes, including nasal congestion or more complex neurological disorders.

The most common temporary loss of smell occurs when we suffer from a cold or allergies. Permanent loss can be linked with the aging process, head trauma, a nutritional disorder, tumor, Alzheimer’s dementia, Parkinson’s, and even tumors. Or, such things as lead poisoning, a viral upper respiratory infection, sinus surgery, lead poisoning, or specific medications may be to blame. A smoking habit will cause an individual to have a weaker sense of smell than will occur in non-smokers. There is also a known link between the long-term use of nasal decongestants, zinc-based products, amphetamines, estrogen, and other prescription drugs causing a diminished or lost sense of smell. Often, a loss of smell is linked with a loss of taste. With nervous system involvement, the individual may experience speech difficulties, visual problems, headaches, behavioral changes, and numbness/weakness on one side of the body.

If you saw an otolaryngologist (an ear/nose and throat specialist) who prescribed antibiotics, he likely thought you were suffering from an upper respiratory infection. Not all infections clear as quickly as we might like but you should have returned to his or her office with an update. The medication could have been changed or an investigation into other possible causes could have begun.

You don’t mention your age but it may be time to sit down with a pencil and paper and list what has transpired since your first observation. I am aware that a loss of smell may be a very early symptom, but are you forgetful, suffer from short-term memory loss, become disoriented to time and place, and misplace things? If the answer is an emphatic no, you just might be able to rule out Alzheimer’s disease. Has your handwriting become cramped and illegible, do you have a gait abnormality and muscular rigidity? If not, perhaps you can also rule out Parkinson’s, as well. If you have concerns, you should definitely make an appointment for a consultation with a neurologist for appropriate testing. Have you been exposed to lead paint or lead-contaminated dust in older buildings and have headaches, pain, numbness and tingling of the extremities, hypertension, a reduced sperm count, and a declined in your mental function? I think you can see where I am going from here. If your doctor isn’t helping, become your own detective. List your symptoms and any other changes you’ve experienced, including swallowing difficulties or masses in your head/neck area. Be sure to include your medications and over-the-counter herbal supplements that could be completely to blame. Then take that information to your primary care physician for review. Undergo lab testing and imaging studies he or she might deem appropriate. In other words, help your doctor help you.

Immediately, and even before getting in to see your doctor, go to your local hardware store and purchase smoke/C02 detectors for your home. If your nose can’t keep you safe, rely on a verbal alarm that will pick up the slack. Good luck.

Readers who would like related information can order Dr. Gott’s Health Reports “Alzheimer’s Disease” and “Parkinson’s Disease” by sending a self-addressed, stamped number 10 envelope and a $2 (for each report) US check or money order payable to Dr. Gott’s Health Reports, PO Box 433, Lakeville, CT 06039. Be sure to mention the title(s) or print an order form from www.AskDrGottMD.com.