VHOSPITAL.CLINIC · Medical Q&A

What Causes Loss of smell?

A complete overview of all potential causes of loss of smell, from benign to serious medical conditions.

What It Means

Loss of smell has many potential causes spanning multiple organ systems. A systematic approach — considering the character, timing, triggers, and associated symptoms — helps identify the most likely cause and guides appropriate management.

Common Causes

  • Infectious causes: viral, bacterial, or fungal pathogens triggering systemic or localised loss of smell
  • Inflammatory/autoimmune: the body's immune response producing loss of smell as a bystander effect
  • Metabolic: disorders of thyroid, adrenal, or blood glucose regulation
  • Structural/mechanical: nerve compression, joint damage, or organ enlargement
  • Underlying conditions: Covid 19 are among the leading identifiable causes

Red Flags — When to Act

  • Unintentional weight loss accompanying loss of smell (possible malignancy or metabolic disease)
  • Night sweats, fever, and loss of smell persisting >2 weeks
  • New loss of smell in someone with a known cancer, immunosuppression, or recent surgery
  • Rapid progression or change in the character of long-standing loss of smell
  • Family history of serious hereditary conditions presenting with loss of smell

What to Do Now

  1. 1.Keep a symptom diary: date, time, severity, triggers, and what improves or worsens loss of smell
  2. 2.Review your medications — many drugs can cause loss of smell as a side effect
  3. 3.Assess lifestyle factors: sleep, diet, alcohol, exercise, and hydration
  4. 4.Use our AI symptom checker to receive a structured differential and guidance
  5. 5.Book a GP appointment for persistent, recurring, or unexplained loss of smell

When to See a Doctor

  • Loss of smell persists beyond 1 week without an obvious cause
  • Severity is moderate-to-severe or worsening over time
  • Any red-flag features are present (see above)

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Frequently Asked Questions

What is the most common cause of loss of smell?

The most common causes of loss of smell in the general population are stress, dehydration, poor sleep, and minor infections. In specific populations, Covid 19 and other underlying conditions account for a significant proportion of cases.

Can medications cause loss of smell?

Yes — many medications list loss of smell as a potential side effect. Common culprits include antihypertensives, antibiotics, NSAIDs, and hormonal treatments. Review your medication list with a pharmacist or doctor if you suspect a drug-related cause.

Is loss of smell always related to a physical cause?

No. Psychological conditions such as anxiety, depression, and stress disorders frequently produce genuine physical loss of smell through the mind-body axis. Psychosomatic loss of smell is a real, measurable phenomenon requiring appropriate treatment.

Related Resources

Possible Causes

  • Infectious causes: viral, bacterial, or fungal pathogens triggering systemic or localised loss of smell
  • Inflammatory/autoimmune: the body's immune response producing loss of smell as a bystander effect
  • Metabolic: disorders of thyroid, adrenal, or blood glucose regulation
  • Structural/mechanical: nerve compression, joint damage, or organ enlargement
loss of smellFull symptom guide

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Medical ReviewvHospital Editorial Team · 2024–2025
Sources:WHOPubMedUpToDateNICE