Loss of sense of smell and taste is one of the recognised signs of Covid-19 infection and is believed to affect over half of patients. Most recover fully within a couple of weeks, but a significant number experience persistent anosmia which may last many months. Individuals may also experience parosmia, a condition in which smells are interpreted as distorted and unpleasant, and/or phantosmia, in which individuals smell things that aren’t there at all.

The reason these symptoms occur appears to be due to Covid-19 attaching to support cells, which cause the olfactory epithelium – the area of tissue in the nose that detects odours – to lose its structure. This, in turn, means olfactory neurones – the nerve cells that transmit information to the brain in order for it to be interpreted as various smells – malfunction. The support cells can regrow, and the olfactory epithelium can heal, but the process takes time, during which the information received and interpreted by the brain may be scrambled.

This can be distressing to deal with, affecting eating and potentially meaning that sufferers don’t get a healthy balanced diet in their attempts to avoid foods they find triggering. It can also sometimes have a negative impact on mental health. Meditation and other relaxation techniques may be helpful, as well as reaching out to, and perhaps supporting, others who are going through a similar experience.