New research suggests that it is a common skin bacteria that causes an itch in skin conditions like eczema.
Photo: Digitally-colorized scanning electron microscopic (SEM) image depicting clumps of methicillin-resistant Staphylococcus aureus (MRSA) bacteria. | via CDC/PHIL
Based on research in mice and in human cells, scientists have shown that the itch that accompanies conditions like eczema is caused by a common bacteria — Staphylococcus aureus.
Explainer: The itch-scratch reflex is a fascinating crossway between pain and pleasure, yet it is often a neglected mechanism that often serves no more than a vague symptom. The new study published in Cell reports how we have misunderstood the mechanism of such persistent itch.
Why it matters: The research experiments also found that treating animals with an anti-clotting medicine blocked the protein PAR1, interrupting the itch-scratch mechanism.
What’s in it for the bacterium: The researchers speculate that scratching could enable the bacteria to spread to distant body sites and other people — similar to how the TB bacterium uses the cough to its advantage.
About one in three people carry S. aureus in their noses but without any illness. However, it is the most common pathogen involved in skin infections worldwide — associated with conditions that cause itchiness like eczema, prurigo nodularis, and psoriasis.
The researchers note that this explanation is just speculation at this point, but they could follow up with a broader outlook: Why do we itch and scratch? Does it help us, or does it help the microbe?”
Why it matters: Even if it is often believed to remove something bothersome from the skin, the itch has been described as one of the most diabolical sensations.
The research may offer scientists a direction to pursue developing treatments for eczema, but they currently aren’t sure how the findings will translate to humans.