Scratching a mosquito bite may provide temporary relief but actually increases inflammation and prolongs the itch. This was reported by Qazaqyia.kz citing Associated Press.
University of Pittsburgh dermatologist Dr. Daniel Kaplan studied allergic contact dermatitis in mice. He applied an irritant to the ears of rodents and observed their scratching. Scratching led to an accumulation of immune cells and increased swelling. Mice that could not scratch had significantly less inflammation.
According to Kaplan, if you don't scratch a mosquito bite, the itch goes away in 5 to 10 minutes, but if you start scratching, it can last a week. Scratching causes pain, and pain-sensing nerve cells release a chemical messenger called substance P, which activates mast cells and worsens inflammation.
In the experiment, mice were fitted with "cones of shame" to prevent scratching, resulting in reduced inflammation. Additionally, scratching lowered levels of Staphylococcus aureus bacteria on the skin, but this benefit is outweighed by the harm.
Kaplan advises avoiding scratching, though he acknowledges it's easier said than done. Antihistamines and other drugs can help relieve itching, but more effective treatments are needed.