Loss of Taste and Smell: An Evidence-Based Guide for Patients

Loss of taste and smell is often temporary and is commonly related to a cold, allergy, sinus inflammation, or another upper respiratory infection. Because smell contributes strongly to flavor perception, many people who believe they have lost taste have primarily lost their sense of smell; an evaluation can identify the cause and guide care when symptoms persist.

Overview: What Loss of Taste and Smell Means

Loss of taste and smell describes a reduced or absent ability to smell odors, taste food, or both. A complete loss of smell is called anosmia, while partial loss is called hyposmia. Changes in taste may include hypogeusia, meaning reduced taste, or dysgeusia, meaning that tastes seem distorted, unpleasant, metallic, or different from usual.

Smell and taste work together closely. The tongue mainly detects sweet, salty, sour, bitter, and savory tastes, while the nose detects the many aromas that create flavor. For this reason, food may seem bland when the nose is blocked or smell is reduced, even if the taste buds are functioning normally. This distinction helps clinicians look for the most likely source of symptoms.

For many people, symptoms improve as a respiratory illness or nasal congestion settles. However, loss of taste and smell can sometimes last longer or have causes that need targeted treatment. A health professional can help determine whether the change is related to the nose and sinuses, a medication, oral health, nerve pathways, or another health condition.

How Symptoms Can Feel in Daily Life

Symptoms vary considerably. Some people cannot smell smoke, perfume, coffee, or food odors. Others notice that familiar smells are weaker than before. Distorted smell, called parosmia, can make ordinary odors smell unpleasant, burnt, chemical-like, or rotten. Phantom smells that occur without an odor present are known as phantosmia.

True taste loss may make it difficult to identify basic tastes. More often, people report that food has lost its flavor, that meals are less enjoyable, or that appetite has changed. Dry mouth, mouth discomfort, a coated tongue, dental problems, and changes in saliva can also affect taste perception.

These changes can influence nutrition, mood, and social life, especially when they continue for weeks or months. Some people eat less because food is unappealing, while others add excess salt or sugar to make food seem more flavorful. Maintaining regular, balanced meals and discussing significant appetite or weight changes with a clinician can help protect overall health.

Common Causes and Risk Factors

Upper respiratory infections are among the most frequent causes of temporary smell and flavor changes. Colds, influenza, COVID-19, and other viral illnesses can affect the lining of the nose and the smell pathways. Nasal congestion may physically prevent odors from reaching smell receptors, while inflammation may affect smell even when the nose does not feel very blocked.

Allergic rhinitis, sinusitis, nasal polyps, and structural nasal problems can also reduce airflow and smell. People may notice symptoms that come and go with seasonal allergies or that are accompanied by sneezing, a runny nose, facial pressure, or ongoing blockage. Chronic sinus symptoms deserve medical assessment because management differs depending on the underlying cause.

Other possible contributors include smoking and exposure to irritants, aging, head injury, dental or gum disease, dry mouth, and some medicines. Less commonly, smell changes may be associated with neurological conditions or other medical disorders. The timing of symptoms, recent illnesses or injuries, and accompanying signs all help clinicians identify the appropriate next steps.

How Clinicians Evaluate Changes in Smell and Taste

A clinician will usually begin by asking when the loss of taste and smell started, whether it was sudden or gradual, and whether there was a recent infection, allergy flare, injury, medication change, or exposure to chemicals. They may also ask about nasal blockage, sinus pain, headache, dental symptoms, changes in memory or movement, and whether symptoms affect one or both sides of the nose.

An examination may include the nose, mouth, throat, ears, and nervous system. Depending on the findings, an ear, nose, and throat specialist may examine the nasal passages more closely using a small camera. Smell or taste testing can sometimes measure the degree of change and provide a baseline for follow-up.

Imaging or laboratory tests are not necessary for everyone. They may be considered when symptoms are unexplained, persistent, one-sided, linked to a significant head injury, or accompanied by concerning neurological or nasal findings. Testing for respiratory infections may be appropriate when symptoms are new and occur with fever, cough, sore throat, body aches, or recent exposure.

Treatment and Recovery Options

Treatment depends on the cause. When nasal inflammation from allergies or a sinus condition is contributing, a clinician may recommend measures to reduce inflammation and improve nasal airflow. This can include saline rinses, allergy management, or other prescribed treatments. It is important not to start or stop prescription medicines without discussing this with the prescribing clinician.

When smell loss follows a viral infection and does not quickly resolve, smell training may be considered. This structured practice involves regularly smelling a small set of distinct, safe scents and focusing on recalling what each scent should smell like. It may support recovery for some people, but improvement is often gradual and results vary. A clinician or ENT specialist can advise whether it is suitable.

There is no single proven treatment that restores smell or taste in every situation. Supplements, strong fragrances, or unproven remedies should not replace medical evaluation, particularly when symptoms are persistent. Recovery can take days to weeks after congestion improves, while post-viral changes may take longer. Follow-up is useful if progress is limited or symptoms evolve.

Self-Care, Nutrition, and Safety While Symptoms Persist

Simple measures can make eating more comfortable while taste and smell are reduced. Choosing foods with varied textures, colors, temperatures, and naturally flavorful ingredients such as herbs, citrus, or gentle spices may improve meal enjoyment. Salt and sugar should not be increased excessively. People with dietary restrictions, reflux, kidney disease, diabetes, or other medical conditions should seek individualized nutrition advice before changing their diet substantially.

Good oral hygiene, adequate hydration, and avoiding smoking or vaping can support mouth and nasal health. If nasal dryness or congestion is present, a clinician may suggest appropriate nasal care. Strong chemical odors, smoke, and unnecessary irritant exposure should be avoided, as they can aggravate nasal symptoms.

Reduced smell creates practical safety concerns. Smoke and carbon monoxide alarms should be working, and household members should check them regularly. Food should be stored safely and checked by date, appearance, and texture rather than smell alone. Gas appliances should be maintained, and a person who cannot smell gas should consider additional safety measures with their household or utility provider.

When to Seek Medical Care

Medical advice is appropriate when loss of taste and smell is sudden, unexplained, lasts beyond recovery from a cold or allergy flare, or significantly affects eating, weight, safety, or quality of life. An appointment is also advisable after a head injury, when symptoms occur on one side only, or when there is persistent nasal blockage, repeated nosebleeds, facial swelling, or severe sinus symptoms.

Urgent medical assessment is needed if smell or taste changes occur with symptoms that may suggest a neurological emergency, such as facial drooping, weakness or numbness on one side, difficulty speaking, severe sudden headache, confusion, fainting, or new trouble walking. Emergency care is also appropriate after a serious head injury or for difficulty breathing.

Acibadem International’s multidisciplinary specialists and JCI-accredited hospitals can assess persistent smell and taste concerns for international patients, including evaluation by relevant ENT, neurological, and other clinical teams when needed. Most cases are not dangerous, but timely assessment can provide reassurance, identify treatable causes, and support safe recovery.

Frequently asked questions

Is loss of taste and smell usually temporary?

Often, yes. Loss of smell and flavor commonly improves after a cold, allergy flare, or other upper respiratory infection resolves. Recovery time varies, and symptoms that persist or worsen should be assessed by a healthcare professional.

Why does food taste bland when the nose is blocked?

Much of what people experience as flavor comes from smell rather than the tongue alone. When the nasal passages are congested, food aromas cannot reach smell receptors effectively. Basic tastes such as sweet, salty, sour, bitter, and savory may still be present.

Can COVID-19 cause loss of taste and smell?

Yes. A new change in smell or taste can occur with COVID-19 and other viral respiratory infections. A person with new symptoms should consider current public health guidance and speak with a clinician about whether testing is appropriate.

Can allergies cause loss of smell?

Yes. Allergies can cause inflammation, mucus production, and nasal congestion that reduce the ability of odors to reach smell receptors. Treating the underlying allergy with clinician-guided care may help improve symptoms.

What is smell training?

Smell training is a regular practice of deliberately smelling several distinct, safe scents while concentrating on recognizing them. It is sometimes recommended for persistent post-viral smell loss. A clinician can explain how to do it safely and whether it is appropriate for the individual.

Should a person be worried about a sudden loss of smell?

Sudden smell loss is often related to a viral illness or nasal inflammation, but it should be considered in context. Medical advice is particularly important when it is unexplained, follows a head injury, persists, or occurs with neurological symptoms such as weakness, speech difficulty, or severe headache.

References

• American Academy of Otolaryngology–Head and Neck Surgery
• National Institute on Deafness and Other Communication Disorders
• Centers for Disease Control and Prevention
• Mayo Clinic
• World Health Organization

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.