Smell and Taste Disorders - Symptoms

Authored by Dr Hayley Willacy, 01 Jun 2017

Reviewed by:
Dr Carl Philpott, 01 Jun 2017

The sense of taste provides five basic different tastes:

  • Sweet.
  • Sour.
  • Salty.
  • Bitter.
  • Umami (the taste of meaty/savoury substances).

Taste is detected by taste receptors found in our taste buds, which are found on the tongue and in our mouths. Information about what we taste is collected by these taste receptors and is sent to the brain.

However, most of the flavour of food is largely due to the smell of food. This is detected by smell receptors, which are found in the lining of the nose, and the smell of food travels from the back of the mouth into the back of the nose.

Smell, like taste, is a chemical sense detected by sensory cells called chemoreceptors. When an odour stimulates the chemoreceptors in the nose that detect smell, they pass on electrical impulses to the brain. The brain then interprets patterns in electrical activity as specific odours and olfactory sensation becomes perception - something we can recognise as smell.

Smell and taste disorders are conditions that result in a decrease, absence or even distortion in the sense of taste and smell. Some of these are a result of a failed development of the smell or taste system, and others are due to the loss later in life.

This may be gradual or sudden and may in some cases have an obvious preceding cause - for example, a head injury or a viral infection.

Complete lack of sense of smell is termed anosmia. Reduced sense of smell is termed hyposmia. Other changes in the sense of smell include smells being different than expected (parosmia) and the perception of smells that are not there (phantosmia). Because of the effect on detection of flavour of food, a lot of smell disorders lead people to believe they also have a taste disorder but taste disorders are rare.

I have never been able to breathe through my left nostril. I can only sleep while lying on my left side. Much sneezing, nasal drip, loss of taste and smell. My nose appears to be straight, but...

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