When can loss of smell happen with COVID-19?

COVID-19 symptoms do not follow an identical timetable for everyone. Smell may become weaker, disappear or become distorted near the beginning of the illness, during it or while other symptoms are settling. Some people notice it without a blocked nose, whereas congestion can make smell harder to detect. The day smell changes cannot confirm when infection started or distinguish COVID-19 from a common cold, allergic rhinitis or sinus disease. Consider the complete symptom pattern and current local health guidance.

If you develop a new smell change, follow current local advice on testing, staying home and limiting close contact while unwell. Write down when it started, along with fever, cough, sore throat, tiredness or nasal symptoms. Rest and drink fluids, and choose foods with safe texture and temperature. Because smell may not warn you about smoke, gas or spoiled food, check alarms and dates visually. Arrange medical advice if the change continues after the illness or affects nutrition and wellbeing.

Do not wait for a particular day if you have difficulty breathing, chest pain, new confusion, unusual sleepiness, severe dehydration or a rapid deterioration; seek urgent medical help. Contact a clinician for persistent smell loss, worsening infection symptoms, or sudden loss after a head injury. Severe headache with weakness, speech trouble or vision changes also requires urgent assessment.

How should I interpret this symptom with my other symptoms? What local testing or contact guidance applies? Could congestion, allergy or sinus disease be contributing? When should persistent smell change be reassessed?