About four out of five Covid-19 patients suffer a partial or total loss of smell, a condition known as anosmia. Many have no other symptoms.

It’s got nothing to do with stuffy noses; it’s all about the havoc the coronavirus wreaks on our nervous systems https://bloom.bg/2MUHjAx 

Many patients recover their sense of smell, or olfaction, quickly. Others smell less (hyposmia) or scent odors wrong (parosmia):

A spouse suddenly smells like a stranger
Wine like cardboard
Sewage like coffee

For some people, it never comes back http://bloom.bg/2MUHjAx 

Smell has long been our most underrated sense, writes @andreaskluth

Perhaps that’s why we know relatively little about it. Claire Hopkins, aka @SnotSurgeon, says the science of olfaction, compared to that of vision or hearing, is still in the Stone Age http://bloom.bg/2MUHjAx 

But that could change. A year into the pandemic, olfaction is one of the hottest scenes in medicine.

There’s now even a Global Consortium for Chemosensory Research, where scientists from more than 60 countries collaborate to learn about Covid and smell http://bloom.bg/2MUHjAx 

The perception of an odor shoots directly from our nasal receptors into our brains, bypassing the thalamus and immediately triggering a memory or emotion.

By contrast, vision, hearing and touch must take several additional synaptic hops http://bloom.bg/2MUHjAx 

The very richness of our smell universe means that we have no vocabulary to describe it adequately.

Being at a loss for words — think back to your most recent wine tasting — we can mistake vision for being the more important sense http://bloom.bg/2MUHjAx 

Yet, the merest whiff can pick up pheromones that trigger various emotions long before the rest of our brain has even formulated a single thought, including:

Fear
Aggression
Love
Intimacy http://bloom.bg/2MUHjAx 

It’s only when smell is gone that people wake up to its vital role. Many sufferers:

Lose their appetite or confidence
Experience a drop in libido
Fall into depression

Parosmia can be even worse, leaving people destabilized, unmoored and estranged http://bloom.bg/2MUHjAx 

Hyperosmia -- or an increased sense of smell -- also exists. It often happens if you’re:

Pregnant
Have epilepsy
Or genetically lucky http://bloom.bg/2MUHjAx 

Take Joy Milne, a retired nurse in Scotland, whose sense of smell is closer to dogs than people. She can even scent diseases:

Alzheimer’s smells like rye bread
Diabetes like nail polish
Cancer like mushrooms http://bloom.bg/2MUHjAx 

Decades before her husband died of Parkinson’s, she realised he was sick because his odor had changed from “purple,” as she describes it, to “brown.”

She’s now helping researchers in Manchester to create a diagnostic test http://bloom.bg/2MUHjAx 

Thanks to the pandemic, we’re now realizing that a healthy smell is essential to our well-being.

Before Covid, people who lost their olfaction rarely got much attention from their doctors or sympathy from loved ones. That’s over now http://bloom.bg/2MUHjAx 

Anosmia, hyposmia and parosmia are finally recognized as serious diseases and promising fields of study, with scientific breakthroughs likely to follow.

Have you suffered from a change in your sense of smell during the pandemic? http://bloom.bg/2MUHjAx