A study led by researchers at the University of Pittsburgh found that scratching activates immune cells known as mast cells, which release compounds that increase swelling and itching, creating an “itch-scratch cycle.”

Using mice, researchers found that animals prevented from scratching developed significantly less swelling and inflammation than those allowed to scratch.

The findings suggest that scratching intensifies the body’s immune response rather than relieving the underlying cause of the itch.

The study also found that pain caused by scratching releases a chemical messenger called substance P, which further activates mast cells and worsens skin irritation.

Researchers noted that while scratching may offer brief relief and could help reduce certain bacteria on the skin, the overall effect is harmful because it prolongs inflammation and delays healing.

Dermatologists recommend avoiding scratching and instead using anti-itch treatments such as hydrocortisone cream, calamine lotion or menthol-based creams to help break the itch-scratch cycle.