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The reason why people with eczema can’t stop scratching has been discovered for the first time by Harvard scientists.
A study carried out by scientists from Harvard Medical School demonstrated, for the first time, that a common skin bacterium – Staphylococcus aureus – can trigger itching by acting directly on nerve cells.
Itch arises from a subset of neurons and acute itching may be a protective response to help us remove something that is irritating our skin. However, chronic itching is not protective and may even be pathological.
To date, the underlying mechanism that activates neurons and causes chronic itching is not well understood. Scientists believed that the itching typical of diseases such as eczema and atopic dermatitis, for example, arose from inflammation of the skin, but new discoveries show that S. aureusin itself, causes itching by instigating a molecular chain reaction which culminates in the desire to scratch.
According to the Telegraphscientists carried out several experiments with laboratory rats, exposing the animals to the bacteria, realizing that it is related to the moment in which the animals begin to itch.
In the background, the bacteria act directly on nerve cells. Staphylococcus aureus Not only does it make animals itchy, it also makes them hypersensitive. Consequently, rats show a more intense reaction when coming into contact with elements that, previously, would not make them want to scratch.
To identify which characteristic of this bacteria triggered the itching, the researchers made small genetic modifications to the microorganisms. In this way, they were able to identify that the person responsible was the V8 enzymewhich activates a protein called PAR1.
Research thus reveals that people with eczema tend to experience this type of itching caused by bacteria. However, the symptom also occurs in people without underlying conditions, as the action of the microorganism aggravates skin inflammation.
The latest discoveries may help explain why common skin conditions, such as eczema and atopic dermatitis, are often accompanied by persistent itching.
The scientific article was published in cell.
