What should you know about loss of sense of smell is called?

Smell depends on air reaching receptors high inside the nose and on signals travelling to the brain. Allergic rhinitis can swell the nasal lining, while chronic sinusitis may cause prolonged inflammation, congestion or discharge. A common cold can temporarily block airflow. COVID-19 can alter smell, and some people report continuing changes after infection as part of Long COVID. Head injury, nasal growths, smoking, ageing and some medicines are other possible contributors.

Smell loss can reduce the flavour of food and make it harder to notice smoke, gas or spoiled food. It does not identify one diagnosis by itself; timing and accompanying symptoms matter.

Record whether the change is complete or partial, when it began, and whether congestion, sneezing, facial pressure, fever or taste change occurred. Manage known allergies as advised and avoid smoke exposure. Check smoke and gas alarms and use dates and appearance to judge food freshness. Arrange a routine appointment when smell loss persists, recurs or affects eating, safety or daily life. A clinician may examine the nose, review medicines and decide whether further assessment is needed.

Seek urgent care for smell loss after a head injury with confusion, repeated vomiting, severe headache, weakness or a seizure. Get prompt help for breathing difficulty, facial swelling, severe eye swelling or rapidly worsening illness. A routine review is suitable for unexplained, persistent or one-sided nasal symptoms, recurrent nosebleeds or ongoing loss without a cold.

Is this anosmia or a partial reduction called hyposmia? Could allergy, sinus disease, infection, injury or a medicine explain it? Should my nasal passages or smell function be assessed? How can I protect myself from household hazards? When is follow-up needed?