Did you know that just like no two persons have the same fingerprints, no two persons smell exactly the same way? The smells pouring out from various parts of the body are unique to an individual, made up of compounds that vary depending on age, diet, sex, metabolism, and health.

A person’s smell escapes not just from their skin, but their breath, blood and urine; and subtle differences reveal just how healthy they are. On average, people smell more aversive when they are sick, says Matt Olsson, an experimental psychologist at the Karolinska Institute in Sweden.

Matching Sicknesses With Their Distinctive Smell

Diabetes Smells Like Rotten Apples

Several diseases have been discovered to harbour signature scents on the body. For example, the trademark odour for diabetes is described as that of rotten apples, caused by low concentrations of acetone released on the breathe

Typhoid Fever

People with typhoid fever are reported to smell like baked bread.

Yellow Fever

People with yellow fever smell like a butchers shop

What About Scrofula?

The glandular disease, Scrofula leaves people smelling like stale beer.

But all these scents are subtle and can only be picked up by a trained nose.

Can You Smell the Sick?

In a 2014 study, Matt Olson’s team injected human volunteers with lipopolysaccaharide (LPS) — a compound known to activate the immune system and inflammatory responses in humans as if they were fighting bacteria.

By injecting eight volunteers with either LPS or a placebo, bodies were made to behave either as if they were sick or healthy. Body odours were then collected from the armpits of t-shirts worn by volunteers, and inspected by a panel of judges whose noses were trained for the occasion.

The odours were sniffed by a panel of 40 who described their intensity and pleasantness. The odours from bodies that had begun to behave as if they were sick were found to smell more aversive — proving that disease smells. Aversive means that the smell was pungent and noxious enough to be repulsive.

This was the first experimental study to show that when you are sick you smell differently. Olsson has also been exploring other sources of tell tale smells — including urine — and their next target is breathe, which is harder to sample and expose people to.

But George Preti, an organic chemist at the Monell Chemical Senses Center believes that when working with more metabolic odours, such as those in urine and breathe, there are many other factors that come into play aside from immune activity. He says:

These can be affected by your diet or you body’s microbiome, which will make it harder to diagnose the situation.

See Also: Show Me Your Blood, Earwax and Sweat; and I Will Tell You Who You Are!