Itching is so common that one seldom gives a heed to it until unless it is accompanied by some serious problems. Apart from that, scientists have had a long struggle in finding out the reason behind any itch. What is it that actually causes the sensation of itching? Why some types of touch cause an itch while others don’t? Why do you have to scratch when a mosquito or a particular plant touches your skin while no scratching is needed when the clothes you wear touch you the whole day? How exactly does the body know that sensations requiring action should be perceived as itchy while the multitude of other, unimportant touches should not?
A new study conducted on mice has brought in focus the answers to all these questions and the reasons for that annoying itch.
Hair is the first contact point
The itching sensation usually occurs following a light touch on the hairy skin of our bodies. This lightest of light touches triggers a response in our body which is to instantly move our hand to the place where it all started and scratch at it so that whatever is causing the problem gets interrupted.
The new study reveals that a specialised group of cells, a subpopulation of “inhibitory spinal interneurons”, which exist in the spine and act as a gateway between the skin and the brain, work to either allow an itch sensation to travel up to the brain or stop it in its path by inhibiting the message.
Types of itches based on the study
Chronic itch:
The researchers in the course of their study found that when they bred mice to have a selective deficiency in these special cells, the mice began to show a horrible amount of itching with such vigour that they ended up removing tufts of hair. This behaviour is seen in people having chronic itch disorder which accounts for almost 8.4% of the general population. So according to the study, if the same results are applied to humans, it may be assumed that chronic itch disorders are caused by a specific deficiency in these special spinal cells. This may help in giving targeted treatments to people suffering from this disorder.
Chemical itch:
It is the kind of itch caused by things like insect bite. So while a simple hair brush will cease with the touch of your hand a chemical itch that is the one caused by an insect bite caused an inflammatory response. Actually, both kinds of itch may subjectively feel the same to you but your body is sending specific information about the kind of itch to your brain, via completely distinct pathways. The researchers call cells like these your “spinal brain” as they are a good example of how your nervous system can produce highly complex behaviours, without your conscious input.
Some previous researches have also shown a complicated relationship between a chemical itch and pain. It was found that a painful touch or heat sensation can actually suppress the feeling of a chemical itch. This is the reason why scratching an itch gives you relief because it is actually the ‘pain of the scratching’ that relieves itching but unfortunately temporarily.
Contagious itch:
Some studies have even gone on to suggest that itching can also be contagious. Yes! There may be a psychological element to itching. While watching a person who is scratching his own itch one can actually feel an itch building up in another. Indeed, a recent study showed that visual and auditory scratch-related stimuli during a lecture caused a significant increase in scratching behaviour in the audience.
Look what a little itch can do. Such complicated science behind that simple annoying itch!
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Author: Technology Vista
