Reduced or altered sense of smell

Sense of smell (olfaction) is a critical part of our day to day lives, and up to 80% of our sense of taste and flavour comes from smell. Changes in smell can occur from a number of reasons, ranging from obstruction of the nose from polyps or allergic inflammation, to problems with the nerves of smell themselves. COVID-19 highlighted the ability for a virus to affect sense of smell, although loss of smell after viral infections was well recognised beforehand. Other problems that can affect the nerves of smell include head injuries, or very rarely, problems inside the brain. We also recognise that smell can deteriorate with the aging process. Alterations in smell can range from a complete loss (anosmia), reduced sensation (hyposmia), phantom smells (phantosmia) or unpleasant smells (cachosmia).

Treatment of loss of smell depends on its cause. If there are obstructive factors, these can be addressed with medication or surgery, depending on the underlying case. Neural losses are more difficult to manage, but often includes the need for examining the nose and scanning of the brain and sinuses.