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Conditions

Smell loss (anosmia and parosmia)

Loss or distortion of the sense of smell, including after viral infection.

Smell disorders include reduced smell (hyposmia), absent smell (anosmia), distorted smell (parosmia), phantom smells (phantosmia) and heightened smell (hyperosmia). They can follow viral infection, including COVID-19, or arise from nasal and sinus disease, head injury, or other causes. The sense of smell is central to flavour, appetite and safety, and its loss can be distressing.

Diagram of an olfactory sensory neuron, showing the cilia that detect odour molecules and the axon carrying the signal to the brain
An olfactory sensory neuron. The cilia at the bottom sit in the mucus at the roof of the nose; the axon at the top carries the signal to the brain. Diagram by Mr Gane.

Assessment and treatment

Assessment includes a history, examination, and where appropriate formal smell testing and imaging. Treatment depends on the cause and may include treating underlying nasal disease, structured smell training, and selected options such as corticosteroids or platelet-rich plasma injections to the olfactory cleft. Our smell training guide in the Learn section explains the daily exercise in detail.

Mr Gane has researched the science of smell since 2007 and was among the first to identify sudden smell loss as a symptom of COVID-19.

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This page is general information and not a substitute for individual medical advice.