I cannot smell anything: causes and when to worry

Why might you suddenly lose your sense of smell?

A sudden change often follows a viral upper respiratory infection, including COVID-19, but allergy, sinus inflammation, nasal polyps, smoking, some medicines and a head injury can also contribute. Ask when the change began, whether taste changed with it, and whether you have congestion, facial pressure, discharge, fever or neurological symptoms. Do not assume that an open nose means the smell nerves are working normally. Smell loss also changes how strongly food seems to taste, because flavour depends on both taste and smell. Avoid testing recovery with cleaning chemicals or smoke. A simple diary can record congestion, infections, new medicines and any returning smells without turning the diary into a diagnosis.

Is it blockage or a nerve problem?

A blocked nose prevents odour molecules reaching the smell area. Congestion, thick mucus, crusting, allergy or polyps make this explanation more likely. If air passes reasonably well but familiar smells remain absent, a sensory pathway problem is possible. Only an examination and, when appropriate, smell testing can distinguish these reliably. A clinician may inspect the nasal passages, review medicines and assess recent infection or injury. Ask about medicines, smoking and previous nasal disease because these details can change the examination. Do not start or stop treatment based only on an internet article. A clinician can decide whether the main problem is inflammation, obstruction, receptor injury or another condition. Follow the safety advice for food, smoke and gas while waiting for review.

Does smell come back by itself?

Many post-infectious changes improve gradually over weeks or months, but recovery is not certain and the course varies. Arrange primary-care or ENT advice if the loss lasts more than a few weeks, keeps returning, follows a head injury or affects eating and safety. Keep smoke detectors working, check food dates and remember that gas leaks may not be noticed.

What is smell training?

Smell training means carefully sniffing a small group of familiar scents twice daily and noticing each one for several months. Use safe, recognisable items rather than putting irritants inside the nose. It is a structured exercise, not a replacement for diagnosis or treatment. Discuss it with a clinician, especially after injury or surgery.

When should you see a doctor?

Seek prompt medical advice for persistent loss, one-sided blockage, recurrent bleeding, foul discharge, facial pain, fever or a change after trauma. Use local emergency services for breathing difficulty, confusion, weakness, severe headache or a serious head injury. For nasal structure or breathing concerns, see the septorhinoplasty treatment page and contact the clinic.