### New Theory on Itching and Potential Treatments for Eczema and Dermatitis Scientists have recently developed a promising new theory about what causes the sensation of itching. Their latest laboratory experiments suggest potentially effective treatments for people suffering from itchy skin due to eczema or dermatitis. In a study published in the journal Cell, researchers found that exposing the skin of mice to the bacteria Staphylococcus aureus triggered the nervous system to send signals from the skin to the brain, causing itching. This bacterium is common, with about 30% of people carrying it in their nose without harm. However, in people with skin conditions like eczema or dermatitis, the balance of microorganisms on the skin is disrupted, making them more susceptible to S. aureus. This new finding challenges the previous belief that itchiness from eczema and dermatitis was due to inflammation. According to Dr. Isaac Chiu, an associate professor at Harvard, the bacterium S. aureus is found on almost every patient with atopic dermatitis and can cause itching by itself. Mice exposed to S. aureus developed severe itching and an itch-scratch cycle that damaged their skin. Researchers managed to block the nervous system's itching signals using a medicine typically used for blood clot issues, suggesting it could be repurposed as an anti-itch treatment. Future research will explore if other microbes can also trigger itching.