Smell disorders: all your questions answered

What are the most common types of smell disorders?

There are a number of different ways in which smells can change. Some people experience a complete loss of the sense of smell, named anosmia. However, for a lot of people some sense of smell remains and it is not as sensitive as it used to be.

Partial loss of sense smell is called hyposmia. Patients suffering from smell loss quite often complain of parosmia. Parosmia means there is a distortion of the sense of smell. Common things such as food, drink or perfume start to smell wrong and often quite unpleasant.

Less commonly, patients can percieve smells that other people cannot smell. Sometimes they smell an unpleasant smell in their own nose due to sinus problems.

Occassionally, some people begin to experience smells that are not there such as the smell of smoke when there is none at all. This is called phantosmia.

With smell disorders, quite often the sense of taste is also affected. This is because most of your ability to distinguish between flavours is due to smelling the food that is in your mouth. Your tongue can only detect basic tastes like salt, sour, sweet or bitter.   

What are the most common causes of smell disorders?

There are a number of reasons that your sense of smell can change or reduce.  One of the most common reasons is viral infections. These include COVID-19 but also a large number of other viruses.

Patients tend to notice a severe reduction in the sense of smell and taste alongside the symptoms of the viral infection itself. This can often recover quite quickly but in some patients, it can be much longer lasting.

Another common reason for reduced or absent smell is chronic rhinosinusitis. People suffering with chronic rhinosinusitis have inflammation in their noses and sinuses and some of them form nasal polyps.

Patients will generally experience nasal congestion and discharge. In many cases, they experience a gradual decline in their sense of smell.

Aging also causes a gradual reduction in the ability to smell things. This varies quite a lot between people, much in the same way that our hearing becomes less sensitive as we age.

When should I be worried about my smell disorder?

It is very rare for a reduced sense of smell to be caused by any serious disease. However, doctors recommend seeking medical attention urgently if you experience an absent sense of smell, at the same time as other symptoms such as a blocked nose on one side, nose bleeds or blood stain discharge from one side of the nose, severe pain, changes in vision or changes in personality.

When should medical attention be sought?

It is recommended to seek medical attention if you have a reduced sense of smell that lasts more than a few weeks. Your GP can often start medical treatment for disorders like chronic rhinosinusitis.ç

However, if you have ongoing problems it can help to see an ENT specialist. At an ENT examination, specialists can examine the nose in much greater detail using nasal endoscopy. This procedure takes under a minute and enables doctors to diagnose common conditions like chronic rhinosinusitis and nasal polyps, as well as any other issues with the nose or sinuses.

In some cases the nose cavity may look completely normal, meaning that the smell los has been caused by a previous viral infection. After diagnosis, doctors will recommend treatment based on the likely cause of the sense of smell problems.

How are smell disorders treated? Is surgery ever required? If so, when?

The treatment of smell disorders depends on the cause. Sometimes recovery can be very gradual so doctors usually recommend continuing treatment for a prolonged period of time.

In patients with smell loss lasting more than a couple of weeks, it is recommended that they begin smell training. It is essentially a process that rehabilitates the sense of smell through repeatedly smelliing a small group of essential oils on a consistent daily basis.

There is evidence that this treatment can improve recovery from smell loss in many patients, especially when it has been caused by a viral infection.

Nasal steriod spray or drops are also recommended. These are particularly likely to help if you have chronic rhinosinusitis. It is not generally possible to perform surgery to improve the sense of smell directly.

However, in patients with chronic rinosinusitis and nasal polyps, having endoscopic sinus surgery as part of your treatment can improve the sense of smell for a proportion of patients.

There is also a mental health impact from persisient smell loss. There are excellent organisations such as absent and fifth sense which provide people with smell loss with information about available treatment, as well as the support of a community of people going through the same difficulties.