Scratching may feel good, but can it make an itch worse?

Scratching has more to do with the brain signals than you can ever imagine


Do you know that itchy feeling that grips you with the unstoppable urge to scratch your back? Before you know it, you have to extend your hand to give into the impulse to scratch the itch again.

Does this cycle keep repeating itself till you are exhausted? Well, there may be more than one explanation behind this nagging feeling. Here are two studies that try to understand the underlying mechanism in the brain that triggers the itching.

Does serotonin increase itching?

One of the body’s most important neurotransmitters, serotonin, is connected to this compulsive itching sensation. According to research published in 2014 by the journal, Neuron, serotonin only temporarily eases the pain.

It simultaneously activates neurons present on the spinal cord that lead to more itching sensations. When the brain activates the signal to control the pain, serotonin is transmitted from the brain to the spinal cord and ultimately reaches the nerve cells causing the itching.

The study by Washington University’s Center for the Study of Itch was also demonstrated on laboratory rats by removing serotonin-producing genes. Soon, they injected a substance into the mice that could make their skin itch. These mice without serotonin did not feel the need to scratch as much as mice with serotonin, thus clearly showing that the less itching the better.

Which region of the brain activates more itching?

Itching is the result of myriad causes from allergic reactions, diseases like psoriasis, chemicals to parasites. It can end badly in skin and tissue damage.

To study this phenomenon more closely, researchers studied brain regions responsible for chemically processing the itch in the body and the specific neurons with cells that express the gastrin-releasing peptide receptor (GRPR). The region of the brain suspected by researchers was the periaqueductal grey as it processes sensory information with respect to pain.

Researchers said that investigation is needed further into which of the molecules in the Tac 1-expressing periaqueductal grey neurons needs to be eliminated with the help of medication.

Is it absolutely necessary to get rid of the itch?

There is a biological reason as to why we feel the need to itch, and to get rid of this impulse may not be good for the immune system since it serves a function.

“Itch sensation plays a key role in detecting harmful substances, especially those that have attached to the skin. As itching leads to scratching behaviour, this allows the animal to get rid of the harmful substances. In some cases, the lesions caused by scratching can evoke strong immune responses, which might help to combat the invaded substances,” senior study author Yan-Gang Sun of the Chinese Academy of Sciences said in a press release issued last year

Source: Medical Daily