Short answer
Anosmia is the complete inability to perceive odours. It differs from hyposmia, in which the sense of smell is reduced, and from parosmia, in which familiar odours are perceived in a distorted way.
Four terms that are often confused
According to the American National Institute on Deafness and Other Communication Disorders, various smell disorders are distinguished.
Hyposmia: you smell less well.
Anosmia: you cannot detect odours.
Parosmia: a familiar scent smells different or distorted.
Phantosmia: you perceive a smell without an external odour source being present.
What can cause anosmia?
Possible causes include infections of the upper respiratory tract, chronic nasal or sinus problems, polyps, head trauma, ageing and certain neurological or other medical conditions. Some medicines or treatments can also affect the sense of smell.
The cause therefore cannot be reliably determined on the basis of a single online symptom.
Why loss of smell matters
Smell contributes strongly to what we experience as taste and aroma. People with anosmia can still perceive basic tastes, but food can seem much flatter because retronasal smell is missing.
In addition, smell has a warning function. Smoke, burning and spoiled food can be noticed less easily.
Can anosmia recover?
That depends on the cause. Some forms are temporary, others long-lasting. For certain smell disorders, olfactory training is used as a rehabilitation method. A doctor can assess whether further diagnostics or treatment is indicated.
When to seek help?
New or unexplained complete loss of smell deserves medical assessment, especially when it occurs after a head injury, does not recover or is accompanied by other symptoms.
Not a perfume problem but a sensory problem
For people who work professionally with scent, it is important not to confuse anosmia with ordinary habituation to a single perfume. If you simply no longer smell your own home scent, adaptation may play a role. With anosmia, many or all scents disappear from perception.