Scars itch because they are in the process of healthy healing. Itching may occur due to damage to the surrounding nerve endings or dryness of the area, as explained by UK Health Centre.
Although there are no definitive answers as to why scars itch, there are several theories on the subject. There are two types of scar itch, states InvincibleTM Scars: acute and chronic. Burn and keloid scar tissues are often the itchiest and result in a chronic itch that lasts over six months after formation of the scar. Itching of scars is often a good sign that the affected area is healing in a healthy way.
Scratching the area can cause the scar to lapse in healing and appear worse, says UK Health Centre. The damage to the nerve endings of the affected area are widely believed to be the cause of the itch that occurs with scars; however, there may be several others factors that cause scars to have an itch. Moving or stretching of the surrounding area of the scar can cause irritation which leads to itching. Another common reason for scar itchiness is dryness of the area. Usually the application of a moisturizer to the area eases the discomfort.