SIMPLE STEPS TO TREAT THAT DISTRESSING LOSS OF SMELL

AS MANY as 1.2 million people in the UK are estimated to have persistent smell disorders due to infection with Covid-19.

The problem typically lasts at least six months and, for some, their sense of smell will never fully return, according to a report in the BMJ in July.

Initially, it may be due to the infection causing inflammation in nasal tissue. But chronic cases may arise from nerve damage.

Covid can interfere with the sensitivity of our olfactory receptors, proteins on the surface of nerve cells in our noses that detect molecules associated with odours, reported researchers at Columbia University in the U.S. in the journal Cell in February.

The problems Covid can cause range from smelling things that are not there (phantosmia) to a complete loss of smell (anosmia).

Our sense of smell often diminishes naturally with age, with an estimated third of over80s affected, but thanks to Covid there is an impetus to find ways to cure it.

Scientists are vying to produce the first ‘robot nose’ — an implant that picks up smell signals and transmits them into the brain.

At Virginia Commonwealth University in the U.S., surgeon Daniel Coelho is developing a device to bypass our normal smell system, in which sensory nerve cells at the top of our nose detect odour molecules and send signals via the olfactory nerve to the olfactory bulb, the area in the brain that processes smell.

The new device aims to detect chemical odours from the air via a sensor that’s worn on spectacles and sends the information to the olfactory bulb (at the bottom of the brain, near the back of the nose).

Carl Philpott, a professor of rhinology and olfactology at the University of East Anglia, is working on a simpler approach, involving vitamin A (retinoic acid) nose drops.

The hope is the vitamin will encourage natural repair in the smelling cells in the lining of the nose.

A study of 170 patients suffering loss of smell, published in the journal European Archives of Oto-Rhino-Laryngology in 2017, showed that 37 per cent treated with the vitamin drops could identify more smells correctly, compared with 23 per cent of patients given a placebo. For his new study, 38 patients will receive a 12-week course of daily nasal vitamin A drops. He hopes to have results early next year.

Meanwhile, stem cells are being suggested as a future therapy, says Graham Wynne, a chemist who is on the scientific advisory board of Fifth Sense, a charity dedicated to smell and taste disorders.

‘A healthy human olfactory system has an efficient and well-known repair system, where the tissues lining the nose replace themselves every few weeks,’ he says.

The repair mechanism can break down, however, due to viral attack or age-related wear and tear. It’s hoped that stem cells may kickstart the repair mechanism.

Marianna Obrist, a professor of multisensory interfaces at University College London, is the co-founder of a company pioneering a high-tech smelltraining therapy.

Smell training involves sniffing and identifying four scents — usually rose, eucalyptus, lemon, and clove — for 15 seconds, twice a day, over several months. This trains people to use their remaining smell sense more accurately and hopefully strengthen it.

You can do smell training at home, by spending 20 seconds sniffing four strong scents.

Professor Obrist’s OWidgets system, currently being trialled, consists of a computercontrolled smell-delivery box (which can emit up to six scents) and a smartphone app that controls the device and reminds you to do the next session.