WASHINGTON (AP) - The urge to scratch a bug bite is powerful, but medical science confirms it creates a vicious cycle. New research from the University of Pittsburgh details exactly how and why scratching worsens skin inflammation.
Dermatologist Dr. Daniel Kaplan's team studied allergic contact dermatitis in mice. Using "cones of shame" to prevent scratching, they found significantly less swelling and fewer inflammatory cells compared to mice that could scratch.
The key is a dual-response in the skin. Scratching causes pain, which triggers the release of a chemical messenger called substance P. This substance activates immune cells called mast cells through a separate pathway from allergens, compounding the inflammatory response.
This cycle is why ignoring a mosquito bite makes the itch disappear quickly, while scratching makes it persist for a week. While scratching may offer minor germ protection, Kaplan states it remains "deleterious" to overall skin health.
For relief, experts recommend hydrocortisone cream, calamine lotion, or oatmeal baths. Kaplan suggests menthol-containing creams, which can "fool" the skin and help break the itch-scratch cycle.