Smelling danger

Do you find that you are not able to smell the aroma of food Are you unable to smell something despite holding it close to your nose Is it due to a disease or a disability

The sense of smell is an integral part of the brain’s functioning and a loss of smell could indicate diseases like Parkinson’s or Alzheimer’s or even a tumour in the brain. Often, people are caught unawares as loss of smell is diagnosed only during investigations.

Causes: In normal cases, loss of smell may be caused by a common cold. While in senior citizens, it may be due to age-related degeneration of nerves. In some people, this condition shows up in middle-age because of continuous exposure to toxic fumes, thinning of nasal mucous membranes, chronic nasal infection and polyp growths in the nose. The other causes are tumours in the front portion of the brain, Parkinson’s, Alzheimer’s, dementia and other neuro-degenerative conditions.

Progression of neuro diseases: Loss of sense of smell can indicate the start of a disease like Parkinson’s, almost 20 years before it is clinically identified. Neuro-degenerative diseases and slow growing brain tumours are often not diagnosed early as patients are unaware of their disability. Dr M. Gopi Srikanth, consultant neurologist at Century Superspeciality Hospitals explains, “In any case of sudden loss of smell, the patient becomes aware as the flavour of food they consume does not give them the smell that they earlier appreciated. In such cases, the sudden loss of smell is recognised early and patients approach doctors faster. Sudden loss of smell can also occur in the case of head injuries, chronic nasal infections and common cold.” Sudden loss of smell can thus be easily identified and treated while progressive cases often go undetected for long periods of time.

Tumour as a cause: Anosmia or loss of sense of smell is frequently seen in drug addicts and patients who are working in chemical factories and exposed to strong solvents. Post-radiation treatment in head and neck cancer patients also causes this condition. The compression of the olfactory nerve can also lead to a loss of sense of smell. Dr Deepika Sirineni, consultant neurologist at Apollo Hospitals explains, “Compression of nerves is usually due to a tumour, which results in this condition. The first step is to diagnose and treat the tumour. People who are constantly exposed to toxic smells and working in places where they have to check strong odours like camphor and different kinds of perfumes are found to suffer from loss of smell due to their professional occupation. They need to be treated on time to restore their basic sense of smell. But many a time, these people come too late.”

Presently, smell identification tests are done in neurology clinics where patients can evaluate their sense of smell.