Cacosmia is a smell disorder defined by the perception of unpleasant or foul odors without there being such odors in the patient’s external environment. This is usually the tip of the iceberg: infection, gastric problem or neurological damage are often the basis of cacosmia.

Definition of cacosmia

Cacosmia is a smell disorder defined by the perception of unpleasant or foul odors without there being such odors in the patient’s external environment and without dysfunction of his olfactory system.

It is often an odor that emanates from the patient’s body. However, the perceived odor can also be the consequence of a neuronal alteration.

Types of cacosmias

Two types of cacosmias can be distinguished:

• Objective cacosmia: the smell, very real, is produced by the patient himself. It can be felt by other people nearby. We speak of endogenous odor;
• The subjective cacosmia: the smell felt is not real and not perceived by those around you. This type of cacosmia remains rare.

Causes of cacosmia

The main causes of objective cacosmia are:

• An infection of the teeth, sinuses – sinus aspergillosis, sinusitis, often caused by dental infection -, tonsils (tonsillitis), etc. ;
• An inflammation of the nasal passages like rhinitis – especially the so-called atrophic one;
• A fungal infestation of the sinuses via the cultivation of fungi such as Scedosporium apiospermum or Pseudallescheria boydii;
• Gastroesophageal reflux disease;
• And rarely, taking esomeprazole: still poorly understood and unclear, taking esomeprazole, as part of a treatment against gastroesophageal reflux, can induce cacosmia.

During a subjective cacosmia, it is often an external stimulus – a flower smell for example – which is perceived as a bad smell. Subjective cacosmia is linked to psychological or neurological reasons. In the latter case, two explanations are possible: either the signal is transmitted erroneously to the central nervous system, or it is transmitted adequately, but is misinterpreted by the central nervous system. The causes of olfactory hallucination can be due to:

• Brain lesions, especially in the temporal lobe;
• Brain tumors affecting the olfactory cortex or the nerve fibers related to it.

Diagnosis of cacosmia

The diagnosis of cacosmia is made first of all on the feelings of the patient himself and his perception of unpleasant odors. The healthcare professional must first make sure that there is no obstruction of the nasal passage. Various examinations are then carried out in order to target the cause of the cacosmia:

• An ENT examination to detect visible inflammations or infections such as those of the tonsils or nasal passages;
• A photograph obtained by magnetic resonance imaging or by CT scan, or endoscopy to locate, if they exist, an infectious focus, brain lesions or a tumor;
• Culture of a tissue sample to demonstrate the presence of a fungus;
• A pH-impedancemetry to measure the acidity of the stomach and diagnose gastroesophageal reflux;
• And many more

People affected by cacosmia

10% of the general population suffers from an odor disorder, of which cacosmia is a representative.

Factors favoring cacosmia

The factors favoring cacosmia are declined according to the causes relating to the pathology:

• Dental infection: poorly treated dental infection that travels to the sinus, accident during dental treatment – for example perforation of the sinus floor by dental implants – decayed teeth;
• Sinus infection: asthma, active or passive smoking;
• Inflammation of the nasal passages: air pollution;
• Tonsil infection: presence of a streptococcal-type bacteria in the body;
• Infestation by a fungus: AIDS, neutropenia – abnormally low number of neutrophils, a type of white blood cell, in the blood -, cancerous diseases of the blood and bone marrow, transplants;
• Gastroesophageal reflux disease: obesity, overweight, tobacco, diet rich in fatty foods;
• Brain injuries: falls, accidents, explosions.
• Brain tumors: radiation, immunosuppression – weakening of the body’s defenses;
• And many more

Perception of unpleasant odors

The patient suffering from cacosmia perceives unpleasant odors not present in the environment and without dysfunction of his olfactory system.

Perception of intact taste

On the other hand, the cacosmia has no effect on the taste perception.

Divergent symptoms

The symptoms of cacosmia differ depending on the causes:

• Sinus infection: sinus congestion, yellow or discolored runny nose, pain when pressing on the sinuses, headache;
• Dental infection: pain – which becomes more and more intense as the infection develops -, sensitivity to hot and cold;
• Fungal infestation: cough, fever possible;
• Tonsil infection: sore throat, fever, wheezing during inspiration (stridor), difficulty in breathing, hyper-salivation, hushed voice, as if the patient had a hot object in the mouth;
• Inflammation of the nasal passages: scabbing, nosebleeds, runny nose, sneezing;
• Gastroesophageal reflux disease: heartburn, acid reflux, bitter taste in the mouth, disturbed sleep;
• Brain damage in the temporal lobe: headaches, visual disturbances, memory disturbances, locomotor disturbances, nausea or vomiting, fatigue, dizziness;
• Brain tumors in the olfactory cortex: olfactory hallucination, epileptic seizures.

Treatment for cacosmia depends on its cause.

A sinus infection can be treated by:

• Essential oils: lemon eucalyptus, to reduce inflammation, black pepper for its analgesic and hyperthermizing effect, field mint, for the decongestant effect, eucalyptus radiata, for its anti-infective power;
• Medicines: antibiotics, such as penicillin to counter bacterial infection, analgesics, such as paracetamol to reduce pain, corticosteroids, to locally reduce edema if necessary;
• Surgery: sinus washing, tooth extraction if necessary, endonasal microsurgery.

A dental infection will be treated through:

• Decontamination of the infected area by a health professional;
• The administration of antibiotics in addition if necessary.

Depending on the inflammation of the nasal passages, the healthcare professional may prescribe the following treatments:

• Humidification of the ambient air;
• Administration of vasoconstrictors or antihistamines.

An infection of the tonsils will be relieved by:

• Administration of ibuprofen or paracetamol;
• Gargling with hot salt water;
• Throat sprays based on local anesthetic;
• The absorption of foods that are easy to swallow, nourishing and moisturizing: the soup is ideal.

Treatments for cacosmia following severe gastric reflux are:

• Surgery, to place a valve between the esophagus and the stomach and thus mechanically block the flow of food;
• Pharmaceutical treatments in addition to surgery since they only act on the symptoms and not on the very cause of the reflux: antacids or gastric dressings, which calm without healing, H2 antihistamines, to reduce the production of hydrochloric acid , proton pump inhibitors, to block cells that make acid.

Apart from severe lesions, natural brain plasticity – the brain’s ability to repair itself – can help heal a brain injury. Otherwise, depending on the location and extent of the brain injury, the patient may undergo various treatments:

• Neurosurgery, to deactivate the damaged part of the brain;
• Occupational therapy, if necessary, to relearn the gestures of daily life;
• Physiotherapy, to work on balance if necessary;
• Speech therapy, to improve oral communication if necessary.

Treatments for cacosmia following a brain tumor are:

• Chemotherapy;
• Radiotherapy;
• Targeted therapy
• Removal of the tumor by surgery if the tumor is large, and this is not considered risky by the healthcare professional.

In the event of an overgrowth of fungi, the main treatment is to take antifungals.

Despite the multiple causes, cacosmia can be prevented by:

• Avoiding contact with people with an infection that could be contagious;
• Maintaining a healthy lifestyle – food, dental etc. ;
• Avoiding going to bed as soon as the meal is finished;
• Using in synergy, on a spoon of honey, the essential oils of basil, peppermint and Roman chamomile to improve the digestive system;
• And many more