Loss of Sense of Smell or Anosmia can cause a great deal of distress for the sufferer.

To understand the loss of the sense of smell, let us first try and understand how we smell?

Chemicals in odorous material enter the nasal passage when we breathe and reach the roof of the nasal cavity where nerve endings specially designed for the special sense of smell reside. The chemical causes a stimulation of these sensory nerve endings which get activated and pass on the impulse to the brain which recognises the odour from the past memory stored in its cells. Interestingly the arc of the sense of smell is the shortest since the top of the nose is in such close proximity to the brain and impulses flow to and fro very quickly. Compare this with a sensation from the tip of your toe to the brain and you will get an idea of how short the nerve impulse has to travel to stimulate the brain about the smell.

The sense of smell is linked to memory - a particular smell taking one back to a particular event or occasion. For instance, the smell of sandalwood always reminds me of my Nursery class teacher since she used to wear that perfume every day to school! 

Since the flavour of the food that we eat arises out a combined ability to smell and taste, loss of sense of smell also affects the taste perception of the food we eat.

Anosmia can be classified into some subtypes:

  • Anosmia - Loss of power of smell
  • Hyposmia - Reduced power of smell
  • Parosmia/ Cacosmia  - Abnormal sensation (usually bad) of smell

CAUSES

Anosmia can be caused by: 

  • Local Causes - In the Nose - like after a bad cold, due to nasal polyps or sinusitis, brain tumours extending down into the nose, injury to the nose or head trauma, following Radiotherapy.
  • General Causes - After Antibiotic use, Cocaine abuse, Alzheimer's, Parkinsonism, Multiple Sclerosis, Old age.

WILL IT GET BETTER?

  • Some patients of Anosmia will improve on their own - like after a common cold.
  • Some will require corrective treatment like decongestant nasal sprays, medical management of sinusitis, surgical removal of polyps or tumours, or other specific treatment.
  • Sometimes the only option the ENT Specialist has is to offer a course of systemic steroids - this help to remove the swelling and inflammation around the nerve - strictly under medical supervision because of the potential side effects of steroids.
  • Smoking dulls the sense of smell and must be stopped.