How to test loss of smell

Congestion from a common cold, allergic rhinitis, or sinus disease can prevent scents reaching smell receptors. COVID-19 and Long COVID can also be associated with smell changes. A weaker sense may affect flavour and reduce your ability to notice smoke or spoiled food.

Use familiar household scents such as coffee, soap, or citrus, held near the nose without touching it. Test one scent at a time, with normal breathing, and record whether it is recognisable, faint, or absent. Do not sniff bleach, ammonia, solvents, essential oils, or other irritants. Repeat the comparison later rather than testing forcefully. Check smoke and gas alarms at home because smell loss can reduce warning of hazards.

Arrange medical advice if loss persists, returns repeatedly, follows a head injury, is mainly on one side, or comes with nasal blockage, facial pain, or discharge. Seek urgent help for sudden smell loss with facial weakness, speech trouble, confusion, severe headache, or breathing difficulty. Persistent symptoms after a cold or COVID-19 also merit review.

Ask whether congestion, allergy, sinus disease, infection, injury, or medicine could explain the change, and whether smell training or further assessment is appropriate. Share the onset, exposures, nasal symptoms, recent illness, and any change in taste.