Can flu cause loss of smell and taste?

The tongue detects basic tastes, while smell supplies much of the detail people experience as flavour. Flu may swell the nasal lining and produce mucus, limiting odour movement to smell receptors. Dry mouth, fatigue and reduced appetite can make eating feel different too. A common cold, allergic rhinitis and chronic sinusitis can produce similar congestion. A sudden change in smell and taste without much nasal blockage can also occur with COVID-19; symptoms that continue after infection may be described as Long COVID.

Rest, drink fluids and select foods with comfortable textures and noticeable but not irritating flavours. Saline nasal care may ease congestion if used as directed. Avoid smoking and strong chemical smells. Because reduced smell affects warning signals, check food freshness and use extra caution with gas, smoke and cleaning products. Keep a simple record of fever, congestion, smell and taste so you can describe the pattern accurately. Follow local testing guidance if COVID-19 is possible.

Speak with a clinician if smell or taste remains reduced after the respiratory illness improves, appears repeatedly, or occurs with facial pain, one-sided nasal blockage, nosebleeds or neurological symptoms. Seek urgent help for severe breathing problems, confusion, fainting or significant dehydration. Assessment can help distinguish lingering inflammation from COVID-19, sinus disease or another problem.

Could congestion explain both changes, or should I test for COVID-19? Do my medicines or allergies matter? When should persistent loss be investigated?