The sense of smell allows the human being to detect and process the smells and aromas around him. Through it, the person can recognize objects, substances and even people around him. As well as identify dangerous situations such as a gas leak, or food in bad condition that could be eaten if the bad smell was not detected.

However, this sense can be altered by different causes. These alterations are known as parosmias and include all the alterations that impair the sense of smell, including cacosmia , which will be discussed throughout this article.

What is cacosmia?

Cacosmia is a strange medical condition whose term comes from the Greek and is formed by kakos whose translation is “bad” and osmé “smell”.

The expression refers to an alteration of the sense of smell in which the brain is incapable of correctly perceiving smells and aromas , specifically the person refers to feeling unpleasant and even pestilential smells when the rest perceive normal aromas or even no smell at all.

According to some sources, in some cases the person may feel some preference for these unpleasant aromas, even exposing himself voluntarily to them.

This perceptive alteration of the sense of smell is common in patients suffering from some kind of illness or psychiatric disorder , as well as in people with physical damage such as epilepsy or deterioration of the nasal cavities.

Cacosmia belongs to a group of conditions of aroma perception called parosmia, which also include hyperosmia, hyposmia and anosmia.

Diagnosis of cacosmia

In the diagnosis of cacosmia, as with all other parosmia, a physical examination of the ears, nose and throat is necessary to determine the origin of the condition or to rule out physical causes. This analysis is carried out by means of an endoscopy, which consists of introducing, for example, a fine tube with a small camera into the nose, which allows the clinician to visualise the nasal cavities from the inside .

Another test carried out in the evaluation of this alteration is that of measuring the patient’s olfactory capacity. For this purpose, the minimum amount of aromas that a person is capable of perceiving is determined. Likewise, a test is also carried out in which the patient is exposed to a series of different aromas and this must determine which odours are involved.

Finally, it is also necessary to review the patient’s medical history, in order to find out if the patient has been exposed to possible toxins .

The inconvenience and interference that an alteration of the sense of smell can produce should not be underestimated, since one of its functions is to be an initial warning signal for a danger such as smoke, gas, decomposing or spoiled food, etc.

The sense of smell also plays an essential role in feeding. Therefore, a person suffering from cacosmia may see his or her eating habits altered , since the smell of food becomes unpleasant as well.

Causes and treatments

Cacosmia can have different causes, both physical and psychological. Therefore, the type of treatment chosen will vary depending on the cause of the problem, hence the importance of a correct diagnosis and a thorough evaluation.

We can differentiate between physical and psychological causes, in which it is an anomalous activity of certain brain areas that causes this alteration.

Brain causes

If the possible physical causes are ruled out, it is very possible that the cacosmia is produced as a consequence of some brain alteration.

This would mean that the perceptual alteration is not due to a bad articulation of the sense, but to an adulteration of the areas of the brain in charge of managing the sensorial functions.

Therefore, the possible causes of cacosmia may be

1. Hypothyroidism

Hypothyroidism is a disease of the endocrine system sometimes caused by a malfunctioning of the immune system, by infections or even during pregnancy.

In these cases, poor thyroid hormone production can trigger both physical and psychological symptoms, and the sense of smell is often affected as well.

2. Epilepsy

Some cases of cacosmia have been reported in temporal lobe epilepsies, these being of a temporary nature. The onset of the cacosmia occurs with one of the seizures and tends to remain for a week or two afterwards.

3. Parkinson’s Disease

Cacosmia is also a symptom seen in some cases of Parkinson’s disease. Although it is not a constant in all patients and the specific cause is not determined, it is theorized that a lack of dopamine may lead to cases of cacosmia .

Physical causes

Physical causes include the following.

1. Chronic sinusitis

Chronic sinusitis consists of emphysema or inflammation of the sinuses as a result of infection by a virus, fungus or bacteria.

The main symptoms of sinusitis are a runny nose, congestion or obstruction of the nasal passages, which makes it very difficult to breathe through the nose. It is also characterized by hypersensitivity, pain and inflammation around the eyes, cheeks or nose. As a consequence this also causes a reduction or alteration of the perception of the senses of taste and even touch .

In some types of chronic sinusitis in which infectious agents are retained in the sinuses, cachemia appears as one of the main symptoms.

Since it is associated with a physical cause, the administration of antibiotic drugs should be sufficient to eradicate the perception of unpleasant odours.

2. Crustal rhinitis

Cacosmia can also be traced to crustal rhinitis, also called ocena. This is a disorder that acts on the nasal mucosa , causing sneezing, itching, nasal packing and mucous secretions.

As with sinusitis, treatment of rhinitis itself should put an end to unpleasant feelings. This is achieved by a combination of nasal washing and antibiotics. However, more severe cases have been reported where surgery has been necessary to relieve the symptoms.

3. Postoperative infection

In this case, the cacosmia is derived from a complication or setback of a surgery of the nasal cavity in which the nasal horns suffer some injury or damage .

Another cause may be the drying up of the nostrils caused by empty nose syndrome.

In either case, the solution is to reduce the diameter of the nasal cavity and to implant small silicone rods by surgery.