Phantosmia, also known as olfactory hallucinations or phantom odors, is a sensory disorder that causes a person to perceive smells that are not actually present in the environment. These phantom smells can be experienced in one or both nostrils and may occur occasionally or constantly. While some individuals report pleasant phantom smells, the odors are more often described as unpleasant.
The Nature of Phantom Smells
These phantom smells can range from pleasant scents, like freshly baked goods, to unpleasant ones such as burning, foul, spoiled, rotten, metallic, or chemical odors. This condition differs from other smell disorders, particularly anosmia and parosmia. Anosmia refers to the complete inability to detect odors, while parosmia involves a distorted perception of existing smells, where familiar scents might smell different and often unpleasant. For instance, someone with parosmia might smell rotten smoke when sniffing a cookie, whereas someone with phantosmia smells smoke when no actual smoke is present.
Both phantosmia and parosmia are classified as qualitative olfactory disorders, meaning the quality of the perceived odor has changed or is entirely fabricated by the brain. In contrast, anosmia is a quantitative disorder, signifying a measurable decrease or total loss of the sense of smell. While phantosmia can be distressing, occasional phantom smells may resolve on their own.
The COVID-19 Connection
SARS-CoV-2 infection has been linked to various olfactory disorders, including phantosmia. While sudden smell loss (anosmia) was a common early symptom of COVID-19, phantosmia can appear weeks or months after the initial infection, sometimes even after an apparent recovery of smell. The prevalence of phantosmia in individuals who experienced COVID-19-related olfactory dysfunction is significant.
This prevalence can increase over time as the duration of smell disorders associated with COVID-19 lengthens, with rates rising significantly over several months. Phantosmia can occur regardless of the initial severity of the COVID-19 illness. While some cases resolve in a few weeks, symptoms can persist for months, or even years, especially if there is underlying neurological involvement.
Impact on Daily Life
Living with phantosmia can significantly affect an individual’s quality of life. The constant perception of unpleasant phantom smells can reduce the enjoyment of food and lead to a decreased appetite, potentially resulting in weight loss. It can also interfere with social interactions and contribute to mental health challenges such as frustration, anxiety, and depression.
Beyond personal discomfort, phantosmia presents safety concerns. Individuals with this condition may be unable to detect actual dangerous odors like smoke from a fire, gas leaks, or spoiled food. This inability to perceive real warning smells highlights a serious practical implication.
Understanding and Managing Phantosmia
The exact causes of phantosmia after COVID-19 are not fully understood, but research is ongoing. Theories suggest it may involve damage to the olfactory neurons or inflammation within the olfactory epithelium and olfactory bulb. Changes in brain regions responsible for processing smell signals may also play a role.
Managing phantosmia often focuses on coping strategies and addressing potential underlying causes. Smell training involves repeatedly sniffing a set of essential oils (such as rose, lemon, eucalyptus, and clove) to stimulate olfactory receptor nerves and help restore normal function. This can be performed at home twice daily for several months. Nasal rinses using saline solutions may help to reduce the sensation of phantom smells. Staying hydrated can also be beneficial.
For individuals experiencing anxiety or distress due to phantosmia, techniques like relaxation exercises, cognitive-behavioral therapy, and mindfulness can help. If phantom smells persist for more than a few weeks or are accompanied by other concerning symptoms, consulting a healthcare professional is advisable for proper diagnosis and personalized guidance.