Losing the ability to smell, medically termed anosmia (or hyposmia for a partial loss), is a common symptom accompanying the common cold. This temporary impairment diminishes the appreciation of food and creates safety hazards by masking smoke or spoiled items. Cold-related smell loss is generally temporary and resolves once the underlying infection clears. Understanding the mechanism and proactive steps for recovery can expedite the return of olfactory function.
Understanding Temporary Smell Loss
The primary reason a common cold reduces the sense of smell is physical blockage within the nasal cavity. Smell relies on odor molecules reaching the olfactory cleft, a small area high up in the nose where the olfactory receptors are located. When the body fights a cold, the immune response causes inflammation and swelling of the nasal lining, known as rhinitis.
This inflammation, combined with the production of thick mucus, physically obstructs the air pathway to the olfactory receptors. This is known as conductive smell loss, where odor molecules cannot travel to the nerve endings. Until the swelling subsides and the mucus drains, odorants are prevented from contacting the sensory neurons necessary for smell detection. In some cases, the virus can also cause temporary damage to these olfactory cells, resulting in a lingering loss even after congestion improves.
Immediate At-Home Relief Strategies
The immediate goal for restoring smell during a cold is to reduce the physical obstruction in the nasal passages. Steam inhalation is a simple, effective method to help thin mucus and reduce inflammation. Standing in a hot, steamy shower or leaning over a bowl of hot water while draping a towel over your head can provide temporary relief. The warm, moist air helps loosen the thick secretions blocking airflow to the olfactory cleft.
Using a humidifier, particularly overnight, introduces moisture into the air, which can soothe irritated nasal passages and prevent mucus from drying out. Maintaining a humidity level between 40% and 60% helps keep the nasal lining moist and secretions more fluid. Saline nasal rinses, administered through a neti pot or similar irrigation device, are highly recommended for flushing out mucus and irritants. This process uses a sterile, buffered saline solution to clear the nasal cavity, directly reducing the physical barrier to the smell receptors.
Olfactory Training for Recovery
If your sense of smell does not immediately return after cold symptoms subside, olfactory training can help stimulate the nerves and accelerate recovery. This process acts like physical therapy for the nose, encouraging the regeneration and function of the olfactory nerves. The training involves the repeated, conscious sniffing of a set of strong, distinct scents twice a day for a minimum of several months.
The standard protocol utilizes four categories of odors: floral, fruity, spicy, and resinous. These are often represented by essential oils such as rose, lemon, clove, and eucalyptus. You should sniff each scent for about 10 to 20 seconds, focusing intently and trying to recall the memory of that odor. After smelling one scent, take a short break before moving on to the next one to prevent olfactory fatigue. Consistency is important, and protocols suggest continuing the training for at least three months before switching to a new set of scents.
When Smell Loss Persists
While most cold-related smell loss resolves within a few days or weeks, the symptom warrants a medical evaluation in certain situations. If the loss of smell, or hyposmia, continues for more than seven to ten days after all other cold symptoms have completely disappeared, it is prudent to consult a healthcare provider. Lingering smell loss may indicate a post-viral effect that requires specific guidance, or it could suggest an underlying issue like chronic sinusitis or nasal polyps.
A doctor’s visit is also necessary if the smell loss occurs suddenly without preceding congestion, or if it is accompanied by other severe symptoms. These signs might include a high fever, severe headache, vision changes, or if the loss of smell is only present on one side of the nose. These symptoms may point toward a condition more serious than a common cold, and a medical professional can rule out other causes.