Why do we experience a loss of taste when we have a runny nose?

Why We Lose Sense of Taste During a Runny Nose

The loss of taste during a runny nose is primarily due to impaired smell function (olfaction), as approximately 95% of what we perceive as "taste" is actually contributed by our sense of smell through retronasal olfaction.

Mechanism of Taste Loss During Rhinitis

When you have a runny nose (rhinitis), several mechanisms contribute to taste impairment:

1. Blocked Retronasal Pathway

   • Nasal congestion and inflammation block the retronasal pathway that connects your nasal cavity to your throat
   • This prevents odor molecules from food from reaching olfactory receptors when you eat 1
   • Without this retronasal olfaction, food flavors are significantly diminished

2. Inflammation of Olfactory Epithelium

   • Rhinitis causes inflammation of the nasal mucosa, including the olfactory epithelium 2
   • This inflammation can temporarily damage or block access to olfactory receptors
   • In allergic rhinitis, 71% of patients with reported olfactory loss have at least one positive allergen skin test 3

3. Mucus Barrier Effect

   • Excessive nasal secretions (rhinorrhea) physically prevent odorant molecules from reaching olfactory receptors
   • This creates a physical barrier between airborne chemicals and sensory neurons 4

Types of Rhinitis Affecting Taste

Different types of rhinitis can affect your sense of taste through olfactory dysfunction:

• Viral Rhinitis (Common Cold)

  • Part of the common cold syndrome, lasting up to 10 days 2
  • Temporary inflammation damages olfactory neurons
  • Most patients experience spontaneous recovery within a few weeks 5

• Allergic Rhinitis

  • Studies show a continuum of olfactory loss severity that parallels increasing nasal-sinus disease 6
  • Patients with allergic rhinitis but without polyps or sinusitis still demonstrate moderate hyposmia 3
  • Allergic processes may directly affect olfactory function even without severe nasal obstruction

• Non-allergic Rhinitis

  • Can cause similar symptoms to allergic rhinitis, including taste impairment
  • Often triggered by irritants, temperature and humidity changes 2

Clinical Significance

• Taste and smell dysfunction have been implicated in:

  • Loss of appetite
  • Unintended weight loss
  • Malnutrition
  • Reduced quality of life 1

• While not life-threatening, persistent taste and smell impairment significantly decreases quality of life 5

Recovery Patterns

• Most cases of taste impairment due to rhinitis resolve when the underlying condition improves
• In viral causes, most patients experience spontaneous recovery within a few weeks 5
• Improvement in olfactory function (and thus taste perception) is inversely correlated with:
  • Severity and duration of loss
  • Age
  • Smoking status
  • Male sex 1

Important Distinction

It's worth noting that what most people perceive as "taste loss" during a runny nose is actually a loss of flavor perception due to impaired retronasal olfaction, rather than true gustatory loss (sweet, sour, salty, bitter, umami) 2. The basic taste sensations may remain intact, but the complex flavors that make food enjoyable are significantly diminished.