Anosmia or what is it called?

Anosmia is a Greek word describing the inability to smell [Greek an-, without; + Greek osmē, odour]. A communication disorder, like being blind or deaf, anosmia is the result of a dysfunction between the sensory cells in the mouth, nose and throat and the rest of the olfactory system. The thousands of sensory cells we each possess interpret the odours we come into contact with. They add the flavour to food and drink, identify people and locations, send warning signals in cases of fire, and act as the trigger to memories.

Odours are made up of chemical substances and everything around us has a chemical stamp that stimulates our olfactory cells. The human nose is capable of detecting & recognising over 10,000 different scents. That sounds a lot, but a dogs nose is over 1,000 times more sensitive. We may not have the most sensitive smell detector on the planet, but coupled with our ability to reason, interpret, analyse and remember, it's up there with the most effective.

To smell an odour, the scent first enters the nasal cavity either directly through the nostrils or via the mouth and throat. Once there they come in to contact with the olfactory epitheliums. These are clusters of receptor smells located roughly in line with your cheek bones. The clusters are covered with tiny hairs called cilia and a thin layer of mucus. Each one of the cells inside the cluster [and there are millions of them] is connected to an olfactory neuron or nerve cell. Odour molecules are picked up by the cilia and transferred to the receptor cell. The information is sent along to the olfactory neuron and from there, directly to the brain for processing. Once the smell pattern is processed, the information is transmitted to other parts of the brain to be learned and remembered.

So, what is anosmia? Damage to the olfactory neurons stops the whole process cold, and the bad news is that once damaged the neurons can not be fixed or replaced. Viral infections, chronic sinusitis, nasal obstructions [such as polyps or tumours], medications, dental work, surgery in the nasal area, contact with irritants and chemicals, head injuries and natural aging are all known causes of anosmia. People that are born with this disability are often found [if they can afford to get all the tests done] to have either polyps or a complete lack of olfactory neurons.

What does all this mean and why should we care? Our world is shaped as much by odour as by colour, shape and sound. To be without the ability to detect odour is often described as being cast adrift in a colourless void. Smell-blind is another accurate term. When we meet people, without our consciously realising it, we detect their pheromones and other smells and make decisions about them - whether we're interested in being friends, lovers or can't stand to be in their presence. In a group, our smell detectors are busy interpreting the odours people are giving off and using that information to pick up on tensions, fear, happiness, grief, and anger. The person that can walk into a crowded room and immediately “read” the atmosphere or sense a friend’s mood usually also has an excellent sense of smell.

Then there’s the warning signals side of being able to detect scent. People who cannot smell smoke do not know they’re in danger until they see or breathe in clouds of the stuff, or see the flames. Same goes for chemical spills, gas leaks, turned food and stale drinks. An anosmic can identify an unlabelled container of clear liquid as innocent water or dangerous chemical by one of two ways. Drink the stuff or stick your nose close enough that pain can be sensed. Anosmics might not be able to smell but they feel the burn of toxic chemical just like everyone else. Neither of these methods are suitable to a long and healthy life.

Just like other disabilities and disorders, anosmia can be experienced in several ways.

1. Normosmia generally relates to people with a normal sense of smell

2. Hyperosmia is increased sensitivity to odours

3. Dysosmia relates to any defect or impairment of the sense of smell, which is most often used to describe distortions of smell

4. Hyposmia is a common form of anosmia and is generally the diminished or partial loss of the sense of smell

5. Parosmia is the distortion of smells. For instance, taking a sniff of fresh-baked bread and smelling week-old socks

6. Phantosmia [phantom smells], smelling an odour [usually bad] when the stimulus for that odour is not in the immediate environment

7. Presbyosmia is the form of anosmia most related to aging

Taste disorders are linked to anosmia as 75% of anything you “taste” is actually flavour and therefore, smell. There are five tastes: bitter, sweet, sour, salty and savoury [also known as umami]. Most anosmics, if not also afflicted with a taste disorder, can taste perfectly fine. It is the nuance of flavour, an important factor in gustation enjoyment, that is missing.

There are four known taste disorders:

1. Hypogeusia is the diminished sense of taste and like hyposmia is common

2. Hypergeusia is the increased sensitivity to taste

3. Ageusia, the complete loss of the sense of taste

4. Dysgeusia, a distorted sense of taste

How can you help? Awareness in friends and relatives makes a big difference to anosmics. Too often have people with anosmia reported the difficulties in getting friends and family to believe and then to remember that they cannot smell, no matter what is shoved in their faces. Having doctors who are aware helps even more; anosmia is not “all in your mind”.

For close family, be alert to situations where an anosmic can get into "trouble" and thoughtful when it comes to talking about smells. Anosmics can be sensitive about their personal body odour. They will either overcompensate or, without a smell to act as a prompt, forget that they need deodorant. Advise on perfumes and after shaves you think suit them and be tactful when it comes to letting them know they've used too much or not enough.

For the anosmics, there are quite a few resources to be found on the web that will be helpful in learning about the condition and linking with others like yourself. The more you know, the more you can explain, and the more you will be understood.