Cacosmia is a disorder of the sense of smell in which smells are perceived as unpleasant, rotten, or even disgusting, even though they are in reality either neutral or not present at all.
When the nose deceives you
The sense of smell is an important part of everyday life. It influences how food tastes, warns us of dangers like smoke or spoiled food, and contributes to our wellbeing. With cacosmia, this delicate system falls out of balance. Suddenly there is a smell of rotten eggs, sewage, or decay, even though other people in the same environment notice nothing unusual. This distorted sense of smell can be very distressing, because it often persists and cannot be got rid of by opening windows or washing.
Cacosmia is a form of what is known as parosmia. This means that smells are perceived in a distorted way. While parosmia can involve changes in any direction, cacosmia specifically refers to unpleasant, disgusting smell perceptions.
How does cacosmia develop?
The causes of cacosmia are varied. Often there is a condition affecting the nasal lining behind it, for example a chronic sinus infection or another infection. Polyps, which are benign growths on the lining of the nose, can also disturb the sense of smell. In some cases, injuries, operations, or a severe cold can cause the fine nerve fibres that carry smells to the brain to become irritated or damaged.
Cacosmia also quite often occurs in connection with neurological conditions, for example after a head injury, in epilepsy, or as part of certain neurodegenerative conditions such as Parkinson's disease or Alzheimer's disease. Tumours in the area of the nose or brain are a less common cause. Certain medications or radiotherapy to the head area can also affect the sense of smell.
Everyday life with a disturbed sense of smell
The distorted perception can significantly affect everyday life. Eating and drinking become unpleasant because even favourite foods suddenly smell "rotten" or "chemical". Many people affected report withdrawing from social situations because they fear smelling unpleasant themselves, or because they are repulsed by smells that others cannot detect at all. This can lead to feelings of insecurity, social withdrawal, and even depression.
The question often arises of whether cacosmia is dangerous or whether it points to a serious condition. In most cases, there is no life-threatening cause. Nevertheless, cacosmia that persists or comes on suddenly should always be assessed by a doctor, in order to rule out serious causes and to be able to treat it appropriately.
What can be done about cacosmia?
Treatment depends on the cause. In the case of a bacterial sinus infection, antibiotics can help, while polyps sometimes require an operation. If the disorder is caused by damage to the smell nerves, the sense of smell may improve over time, though this can sometimes take several months. Special smell training, in which a variety of scents are consciously experienced on a regular basis, can support the healing process.
If neurological conditions or medications are suspected as the cause, working closely with doctors is advisable. In some cases, medication can be adjusted or the underlying condition treated more precisely.
Even if there is no specific therapy for every form of cacosmia, simply knowing that the symptoms are being taken seriously and that there are medical approaches to bring relief is often helpful.
When should medical advice be sought?
If cacosmia lasts for a long time, gets worse, or if additional symptoms such as headaches, visual disturbances, or a general decline in health occur, it is important to see a doctor. Particularly after head injuries, operations, or in connection with other neurological signs, there should be no hesitation in seeking medical advice. If the symptoms are very distressing or eating and drinking becomes a struggle, it is worth making an appointment with an ear, nose, and throat specialist.
Cacosmia is rare, but it can significantly reduce quality of life. A thorough assessment and an open conversation with specialists can help to find the cause and identify suitable ways to improve things.
