Types of smell loss

Smell loss affects millions of people worldwide. Estimates vary, but around one person in 20 is affected by smell disorders.

Most people become aware of smell loss when they lose the ability to taste food. In most cases, smell and taste will return normally after a couple of weeks. If smell and taste don't return after three weeks, make an appointment to discuss this with a doctor. We have a 'talking to my doctor' document which you can take with you to your appointment.

What causes smell loss?

  • Viral infection, such as cold, flu or Covid-19.
  • Head trauma
  • Allergies, such as hay fever.
  • Nasal polyps, benign growths in the tissues lining of your nose.
  • Ageing
  • Some medications
  • Radiation treatment for head and neck cancers.
  • Exposure to dangerous chemicals such as pesticides or solvents.
  • Abuse of cocaine and other drugs inhaled through the nose.
  • Smoking
  • Poor air quality
  • Some neurodegenerative conditions such as Parkinson’s disease, Alzheimer's disease, or brain tumours.

Definitions of smell loss 

  • Anosmia is a complete absence of the sense of smell.
  • Acquired anosmia is a result of illness or injury. People with congenital anosmia are born without smell.
  • Hyposmia is a reduced sense of smell. 
  • Idiopathic smell loss is when the cause of anosmia is not known.
  • Normosmia a normal sense of smell.
  • Parosmia is a distorted sense of smell.
  • Phantosmia is when you experience smells that aren’t there. 
  • Ageusia is the absence of gustation (true taste: salty, sweet, sour, bitter and savoury (umami). 
  • Dysgeusia is distorted gustation, for instance a metallic taste
  • Flavour is a combination of smell and taste, but it is mostly smell that enables us to enjoy flavour.