Why do we get itch's

Answer: Wool, chemicals, soaps and other substances can irritate the skin and cause itching. Sometimes the substance, such as poison ivy, parasites or cosmetics, causes an allergic reaction. Also, reactions to certain drugs, such as narcotic pain medications (opioids) can cause itchy skin.

To protect your skin.

Explanation:

The itch sensation is technically known as pruritus, and it's thought to have evolved as a way to protect skin - our largest organ - from parasites and build-up of dead cells.